Merge branch 'master' of https://github.com/apache/commons-lang into fix_FastDateParserTest

pom.xml

@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.commons</groupId>
     <artifactId>commons-parent</artifactId>
-    <version>50</version>
+    <version>51</version>
   </parent>
   <modelVersion>4.0.0</modelVersion>
   <artifactId>commons-lang3</artifactId>
@@ -612,8 +612,8 @@
     <uberjar.name>benchmarks</uberjar.name>
 
     <commons.jacoco.version>0.8.5</commons.jacoco.version>
-    <commons.surefire.version>3.0.0-M4</commons.surefire.version>
+    <commons.surefire.version>3.0.0-M5</commons.surefire.version>
-    <commons.javadoc.version>3.1.1</commons.javadoc.version>
+    <commons.javadoc.version>3.2.0</commons.javadoc.version>
 
     <!-- never generate report if there are binary incompatible changes -->
     <commons.japicmp.breakBuildOnBinaryIncompatibleModifications>true</commons.japicmp.breakBuildOnBinaryIncompatibleModifications>
@@ -764,7 +764,7 @@
           <dependency>
             <groupId>com.github.spotbugs</groupId>
             <artifactId>spotbugs</artifactId>
-            <version>4.0.4</version>
+            <version>4.0.6</version>
          </dependency>
         </dependencies>        
         <configuration>
@@ -778,7 +778,7 @@
           <dependency>
             <groupId>biz.aQute.bnd</groupId>
             <artifactId>biz.aQute.bndlib</artifactId>
-            <version>5.1.0</version>
+            <version>5.1.1</version>
           </dependency>
         </dependencies>
       </plugin>

src/changes/changes.xml

@@ -48,10 +48,6 @@ The <action> type attribute can be add,update,fix,remove.
   <release version="3.11" date="2020-MM-DD" description="New features and bug fixes..">
     <action                   type="update" dev="kinow" due-to="XenoAmess">remove encoding and docEncoding and use inherited values from commons-parent</action>
     <action                   type="fix"    dev="kinow" due-to="contextshuffling">Fix Javadoc for StringUtils.appendIfMissingIgnoreCase() #507.</action>
-    <action                   type="update" dev="ggregory">org.junit-pioneer:junit-pioneer 0.5.4 -> 0.6.0.</action>
-    <action                   type="update" dev="ggregory">org.junit.jupiter:junit-jupiter 5.6.0 -> 5.6.1.</action>
-    <action                   type="update" dev="ggregory">com.github.spotbugs:spotbugs 4.0.0 -> 4.0.4.</action>
-    <action                   type="update" dev="ggregory">com.puppycrawl.tools:checkstyle 8.29 -> 8.33.</action>
     <action                   type="update" dev="ggregory" due-to="Isira Seneviratne, Bruno P. Kinoshita">Simplify null checks in Pair.hashCode() using Objects.hashCode(). #517.</action>
     <action                   type="update" dev="ggregory" due-to="Isira Seneviratne, Bruno P. Kinoshita">Simplify null checks in Triple.hashCode() using Objects.hashCode(). #516.</action>
     <action                   type="update" dev="ggregory" due-to="Isira Seneviratne, Bruno P. Kinoshita">Simplify some if statements in StringUtils. #521.</action>
@@ -75,9 +71,20 @@ The <action> type attribute can be add,update,fix,remove.
     <action issue="LANG-1558" type="update" dev="ggregory" due-to="XenoAmess">Simplify if as some conditions are covered by others #543.</action>
     <action issue="LANG-1528" type="fix" dev="ggregory" due-to="Edwin Delgado H">StringUtils.replaceEachRepeatedly gives IllegalStateException #505.</action>
     <action issue="LANG-1570" type="add" dev="ggregory" due-to="Edgar Asatryan">Add JavaVersion enum constants for Java 14 and 15. #553.</action>
+    <action                   type="add" dev="ggregory" due-to="Gary Gregory">Add JavaVersion enum constants for Java 16.</action>
     <action issue="LANG-1556" type="add" dev="ggregory" due-to="XenoAmess">Use Java 8 lambdas and Map operations.</action>
     <action issue="LANG-1565" type="add" dev="ggregory" due-to="XenoAmess">Change removeLastFieldSeparator to use endsWith #550.</action>
     <action issue="LANG-1557" type="add" dev="ggregory" due-to="XenoAmess, Gary Gregory">Change a Pattern to a static final field, for not letting it compile each time the function invoked. #542.</action>
+    <action                   type="add" dev="ggregory">Add ImmutablePair factory methods left() and right().</action>
+    <action                   type="add" dev="ggregory">Add ObjectUtils.toString(Object, Supplier&lt;String&gt;).</action>
+    <action issue="LANG-1567" type="update" dev="ggregory" due-to="Miguel Muñoz, Bruno P. Kinoshita, Gary Gregory">Fixed Javadocs for setTestRecursive() #556.</action>
+    <action issue="LANG-1542" type="update" dev="ggregory" due-to=" Trần Ngọc Khoa, Gary Gregory">ToStringBuilder.reflectionToString - Wrong JSON format when object has a List of Enum.</action>
+    <action                   type="update" dev="ggregory">org.apache.commons:commons-parent 50 -> 51.</action>
+    <action                   type="update" dev="ggregory">org.junit-pioneer:junit-pioneer 0.5.4 -> 0.6.0.</action>
+    <action                   type="update" dev="ggregory">org.junit.jupiter:junit-jupiter 5.6.0 -> 5.6.1.</action>
+    <action                   type="update" dev="ggregory">com.github.spotbugs:spotbugs 4.0.0 -> 4.0.6.</action>
+    <action                   type="update" dev="ggregory">com.puppycrawl.tools:checkstyle 8.29 -> 8.33.</action>
+    <action                   type="update" dev="ggregory">commons.surefire.version 3.0.0-M4 -> 3.0.0-M5..</action>
   </release>
 
   <release version="3.10" date="2020-03-22" description="New features and bug fixes. Requires Java 8, supports Java 9, 10, 11.">

src/main/java/org/apache/commons/lang3/ArchUtils.java

@@ -16,12 +16,12 @@
  */
 package org.apache.commons.lang3;
 
-import org.apache.commons.lang3.arch.Processor;
-
 import java.util.HashMap;
 import java.util.Map;
 import java.util.stream.Stream;
 
+import org.apache.commons.lang3.arch.Processor;
+
 /**
  * An utility class for the os.arch System Property. The class defines methods for
  * identifying the architecture of the current JVM.

src/main/java/org/apache/commons/lang3/CharSequenceUtils.java

@@ -295,8 +295,8 @@ static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, fi
             }
 
             // The real same check as in String.regionMatches():
-            char u1 = Character.toUpperCase(c1);
+            final char u1 = Character.toUpperCase(c1);
-            char u2 = Character.toUpperCase(c2);
+            final char u2 = Character.toUpperCase(c2);
             if (u1 != u2 && Character.toLowerCase(u1) != Character.toLowerCase(u2)) {
                 return false;
             }

src/main/java/org/apache/commons/lang3/Functions.java

@@ -33,13 +33,6 @@
 
 import org.apache.commons.lang3.Streams.FailableStream;
 import org.apache.commons.lang3.function.FailableBooleanSupplier;
-import org.apache.commons.lang3.function.FailableDoubleBinaryOperator;
-import org.apache.commons.lang3.function.FailableDoubleConsumer;
-import org.apache.commons.lang3.function.FailableDoubleSupplier;
-import org.apache.commons.lang3.function.FailableIntConsumer;
-import org.apache.commons.lang3.function.FailableIntSupplier;
-import org.apache.commons.lang3.function.FailableLongConsumer;
-import org.apache.commons.lang3.function.FailableLongSupplier;
 
 /**
  * This class provides utility functions, and classes for working with the {@code java.util.function} package, or more
@@ -313,42 +306,6 @@ public static <O, T extends Throwable> void accept(final FailableConsumer<O, T>
         run(() -> consumer.accept(object));
     }
 
-    /**
-     * Consumes a consumer and rethrows any exception as a {@link RuntimeException}.
-     *
-     * @param consumer the consumer to consume
-     * @param value the value to consume by {@code consumer}
-     * @param <T> the type of checked exception the consumer may throw
-     * @since 3.11
-     */
-    public static <T extends Throwable> void accept(final FailableDoubleConsumer<T> consumer, final double value) {
-        run(() -> consumer.accept(value));
-    }
-
-    /**
-     * Consumes a consumer and rethrows any exception as a {@link RuntimeException}.
-     *
-     * @param consumer the consumer to consume
-     * @param value the value to consume by {@code consumer}
-     * @param <T> the type of checked exception the consumer may throw
-     * @since 3.11
-     */
-    public static <T extends Throwable> void accept(final FailableIntConsumer<T> consumer, final int value) {
-        run(() -> consumer.accept(value));
-    }
-
-    /**
-     * Consumes a consumer and rethrows any exception as a {@link RuntimeException}.
-     *
-     * @param consumer the consumer to consume
-     * @param value the value to consume by {@code consumer}
-     * @param <T> the type of checked exception the consumer may throw
-     * @since 3.11
-     */
-    public static <T extends Throwable> void accept(final FailableLongConsumer<T> consumer, final long value) {
-        run(() -> consumer.accept(value));
-    }
-
     /**
      * Applies a function and rethrows any exception as a {@link RuntimeException}.
      *
@@ -380,21 +337,6 @@ public static <I, O, T extends Throwable> O apply(final FailableFunction<I, O, T
         return get(() -> function.apply(input));
     }
 
-    /**
-     * Applies a function and rethrows any exception as a {@link RuntimeException}.
-     *
-     * @param function the function to apply
-     * @param left the first input to apply {@code function} on
-     * @param right the second input to apply {@code function} on
-     * @param <T> the type of checked exception the function may throw
-     * @return the value returned from the function
-     * @since 3.11
-     */
-    public static <T extends Throwable> double applyAsDouble(final FailableDoubleBinaryOperator<T> function,
-        final double left, final double right) {
-        return getAsDouble(() -> function.applyAsDouble(left, right));
-    }
-
     /**
      * Converts the given {@link FailableBiConsumer} into a standard {@link BiConsumer}.
      *
@@ -542,9 +484,8 @@ public static <O, T extends Throwable> O get(final FailableSupplier<O, T> suppli
      * @param supplier The boolean supplier to invoke.
      * @param <T> The type of checked exception, which the supplier can throw.
      * @return The boolean, which has been created by the supplier
-     * @since 3.11
      */
-    public static <T extends Throwable> boolean getAsBoolean(final FailableBooleanSupplier<T> supplier) {
+    private static <T extends Throwable> boolean getAsBoolean(final FailableBooleanSupplier<T> supplier) {
         try {
             return supplier.getAsBoolean();
         } catch (final Throwable t) {
@@ -552,54 +493,6 @@ public static <T extends Throwable> boolean getAsBoolean(final FailableBooleanSu
         }
     }
 
-    /**
-     * Invokes a double supplier, and returns the result.
-     *
-     * @param supplier The double supplier to invoke.
-     * @param <T> The type of checked exception, which the supplier can throw.
-     * @return The boolean, which has been created by the supplier
-     * @since 3.11
-     */
-    public static <T extends Throwable> double getAsDouble(final FailableDoubleSupplier<T> supplier) {
-        try {
-            return supplier.getAsDouble();
-        } catch (final Throwable t) {
-            throw rethrow(t);
-        }
-    }
-
-    /**
-     * Invokes an int supplier, and returns the result.
-     *
-     * @param supplier The int supplier to invoke.
-     * @param <T> The type of checked exception, which the supplier can throw.
-     * @return The boolean, which has been created by the supplier
-     * @since 3.11
-     */
-    public static <T extends Throwable> int getAsInt(final FailableIntSupplier<T> supplier) {
-        try {
-            return supplier.getAsInt();
-        } catch (final Throwable t) {
-            throw rethrow(t);
-        }
-    }
-
-    /**
-     * Invokes a long supplier, and returns the result.
-     *
-     * @param supplier The long supplier to invoke.
-     * @param <T> The type of checked exception, which the supplier can throw.
-     * @return The boolean, which has been created by the supplier
-     * @since 3.11
-     */
-    public static <T extends Throwable> long getAsLong(final FailableLongSupplier<T> supplier) {
-        try {
-            return supplier.getAsLong();
-        } catch (final Throwable t) {
-            throw rethrow(t);
-        }
-    }
-
     /**
      * <p>
      * Rethrows a {@link Throwable} as an unchecked exception. If the argument is already unchecked, namely a
@@ -697,7 +590,7 @@ public static <O> FailableStream<O> stream(final Stream<O> stream) {
      */
     public static <O1, O2, T extends Throwable> boolean test(final FailableBiPredicate<O1, O2, T> predicate,
         final O1 object1, final O2 object2) {
-        return get(() -> predicate.test(object1, object2));
+        return getAsBoolean(() -> predicate.test(object1, object2));
     }
 
     /**
@@ -710,7 +603,7 @@ public static <O1, O2, T extends Throwable> boolean test(final FailableBiPredica
      * @return the boolean value returned by the predicate
      */
     public static <O, T extends Throwable> boolean test(final FailablePredicate<O, T> predicate, final O object) {
-        return get(() -> predicate.test(object));
+        return getAsBoolean(() -> predicate.test(object));
     }
 
     /**

src/main/java/org/apache/commons/lang3/JavaVersion.java

@@ -129,6 +129,13 @@ public enum JavaVersion {
      */
     JAVA_15(15.0f, "15"),
 
+    /**
+     * Java 16
+     *
+     * @since 3.11
+     */
+    JAVA_16(16.0f, "16"),
+
     /**
      * The most recent java version. Mainly introduced to avoid to break when a new version of Java is used.
      */
@@ -242,6 +249,8 @@ static JavaVersion get(final String nom) {
             return JAVA_14;
         } else if ("15".equals(nom)) {
             return JAVA_15;
+        } else if ("16".equals(nom)) {
+            return JAVA_16;
         }
         final float v = toFloatVersion(nom);
         if ((v - 1.) < 1.) { // then we need to check decimals > .9

src/main/java/org/apache/commons/lang3/StringUtils.java

@@ -21,11 +21,11 @@
 import java.text.Normalizer;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
-import java.util.HashSet;
 import java.util.Set;
 import java.util.function.Supplier;
 import java.util.regex.Pattern;
@@ -6693,8 +6693,8 @@ private static String replaceEach(
 
         // if recursing, this shouldn't be less than 0
         if (timeToLive < 0) {
-            Set<String> searchSet = new HashSet<>(Arrays.asList(searchList));
+            final Set<String> searchSet = new HashSet<>(Arrays.asList(searchList));
-            Set<String> replacementSet = new HashSet<>(Arrays.asList(replacementList));
+            final Set<String> replacementSet = new HashSet<>(Arrays.asList(replacementList));
             searchSet.retainAll(replacementSet);
             if (searchSet.size() > 0) {
                 throw new IllegalStateException("Aborting to protect against StackOverflowError - " +
@@ -8277,7 +8277,7 @@ public static String[] stripAll(final String... strs) {
      * @return the stripped Strings, {@code null} if null array input
      */
     public static String[] stripAll(final String[] strs, final String stripChars) {
-        int strsLen = ArrayUtils.getLength(strs);
+        final int strsLen = ArrayUtils.getLength(strs);
         if (strsLen == 0) {
             return strs;
         }

src/main/java/org/apache/commons/lang3/builder/EqualsBuilder.java

@@ -245,9 +245,12 @@ public EqualsBuilder setTestTransients(final boolean testTransients) {
     }
 
     /**
-     * Set whether to include transient fields when reflectively comparing objects.
+     * Set whether to test fields recursively, instead of using their equals method, when reflectively comparing objects.
+     * String objects, which cache a hash value, are automatically excluded from recursive testing.
+     * You may specify other exceptions by calling {@link #setBypassReflectionClasses(List)}.
      * @param testRecursive whether to do a recursive test
      * @return EqualsBuilder - used to chain calls.
+     * @see #setBypassReflectionClasses(List)
      * @since 3.6
      */
     public EqualsBuilder setTestRecursive(final boolean testRecursive) {
@@ -265,6 +268,7 @@ public EqualsBuilder setTestRecursive(final boolean testRecursive) {
      * your own set of classes here, remember to include {@code String} class, too.</p>
      * @param bypassReflectionClasses  classes to bypass reflection test
      * @return EqualsBuilder - used to chain calls.
+     * @see #setTestRecursive(boolean)
      * @since 3.8
      */
     public EqualsBuilder setBypassReflectionClasses(final List<Class<?>> bypassReflectionClasses) {

src/main/java/org/apache/commons/lang3/builder/ToStringExclude.java

@@ -19,8 +19,8 @@
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
-import java.lang.annotation.Target;
 import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
 
 /**
  * Use this annotation to exclude a field from being used by

src/main/java/org/apache/commons/lang3/builder/ToStringStyle.java

@@ -624,6 +624,16 @@ protected void appendDetail(final StringBuffer buffer, final String fieldName, f
      *  {@code toString}, not {@code null}
      */
     protected void appendDetail(final StringBuffer buffer, final String fieldName, final Collection<?> coll) {
+        if (coll != null && !coll.isEmpty()) {
+            buffer.append(arrayStart);
+            int i = 0;
+            for (final Object item : coll) {
+                appendDetail(buffer, fieldName, i++, item);
+            }
+            buffer.append(arrayEnd);
+            return;
+        }
+
         buffer.append(coll);
     }
 
@@ -919,18 +929,31 @@ protected void appendDetail(final StringBuffer buffer, final String fieldName, f
         buffer.append(arrayStart);
         for (int i = 0; i < array.length; i++) {
             final Object item = array[i];
+            appendDetail(buffer, fieldName, i, item);
+        }
+        buffer.append(arrayEnd);
+    }
+
+    /**
+     * <p>Append to the {@code toString} the detail of an
+     * {@code Object} array item.</p>
+     *
+     * @param buffer  the {@code StringBuffer} to populate
+     * @param fieldName  the field name, typically not used as already appended
+     * @param i the array item index to add
+     * @param item the array item to add
+     * @since 3.11
+     */
+    protected void appendDetail(final StringBuffer buffer, final String fieldName, final int i, final Object item) {
         if (i > 0) {
             buffer.append(arraySeparator);
         }
         if (item == null) {
             appendNullText(buffer, fieldName);
-
         } else {
             appendInternal(buffer, fieldName, item, arrayContentDetail);
         }
     }
-        buffer.append(arrayEnd);
-    }
 
     /**
      * <p>Append to the {@code toString} the detail of an array type.</p>
@@ -946,15 +969,7 @@ protected void reflectionAppendArrayDetail(final StringBuffer buffer, final Stri
         final int length = Array.getLength(array);
         for (int i = 0; i < length; i++) {
             final Object item = Array.get(array, i);
-            if (i > 0) {
+            appendDetail(buffer, fieldName, i, item);
-                buffer.append(arraySeparator);
-            }
-            if (item == null) {
-                appendNullText(buffer, fieldName);
-
-            } else {
-                appendInternal(buffer, fieldName, item, arrayContentDetail);
-            }
         }
         buffer.append(arrayEnd);
     }

src/main/java/org/apache/commons/lang3/concurrent/Locks.java

@@ -39,30 +39,30 @@
  * the lock.</li>
  * <li>If you want to access the locked object, create a {@link FailableConsumer}. The consumer will receive the locked
  * object as a parameter. For convenience, the consumer may be implemented as a Lambda. Then invoke
- * {@link Locks.Lock#runReadLocked(FailableConsumer)}, or {@link Locks.Lock#runWriteLocked(FailableConsumer)}, passing
+ * {@link Locks.Lock#acceptReadLocked(FailableConsumer)}, or {@link Locks.Lock#acceptWriteLocked(FailableConsumer)}, passing
  * the consumer.</li>
  * <li>As an alternative, if you need to produce a result object, you may use a {@link FailableFunction}. This function
  * may also be implemented as a Lambda. To have the function executed, invoke
- * {@link Locks.Lock#callReadLocked(FailableFunction)}, or {@link Locks.Lock#callWriteLocked(FailableFunction)}.</li>
+ * {@link Locks.Lock#applyReadLocked(FailableFunction)}, or {@link Locks.Lock#applyWriteLocked(FailableFunction)}.</li>
  * </ol>
  *
  * Example: A thread safe logger class.
  *
  * <pre>
  *   public class SimpleLogger {
+ *
  *     private final Lock&lt;PrintStream&gt; lock;
  *
  *     public SimpleLogger(OutputStream out) {
- *         PrintStream ps = new PrintStream(out);
+ *         lock = Locks.lock(new PrintStream(out));
- *         lock = Locks.lock(ps);
  *     }
  *
  *     public void log(String message) {
- *         lock.runWriteLocked((ps) -&gt; ps.println(message));
+ *         lock.acceptWriteLocked((ps) -&gt; ps.println(message));
  *     }
  *
  *     public void log(byte[] buffer) {
- *         lock.runWriteLocked((ps) -&gt; { ps.write(buffer); ps.println(); });
+ *         lock.acceptWriteLocked((ps) -&gt; { ps.write(buffer); ps.println(); });
  *     }
  * </pre>
  *
@@ -71,30 +71,31 @@
 public class Locks {
 
     public static class Lock<O extends Object> {
-        private final O lockedObject;
+
         private final StampedLock lock = new StampedLock();
+        private final O lockedObject;
 
         public Lock(final O lockedObject) {
             this.lockedObject = Objects.requireNonNull(lockedObject, "Locked Object");
         }
 
-        public void runReadLocked(final FailableConsumer<O, ?> consumer) {
+        public void acceptReadLocked(final FailableConsumer<O, ?> consumer) {
-            acceptLocked(() -> lock.readLock(), consumer);
+            lockAcceptUnlock(() -> lock.readLock(), consumer);
         }
 
-        public void runWriteLocked(final FailableConsumer<O, ?> consumer) {
+        public void acceptWriteLocked(final FailableConsumer<O, ?> consumer) {
-            acceptLocked(() -> lock.writeLock(), consumer);
+            lockAcceptUnlock(() -> lock.writeLock(), consumer);
         }
 
-        public <T> T callReadLocked(final FailableFunction<O, T, ?> function) {
+        public <T> T applyReadLocked(final FailableFunction<O, T, ?> function) {
-            return applyLocked(() -> lock.readLock(), function);
+            return lockApplyUnlock(() -> lock.readLock(), function);
         }
 
-        public <T> T callWriteLocked(final FailableFunction<O, T, ?> function) {
+        public <T> T applyWriteLocked(final FailableFunction<O, T, ?> function) {
-            return applyLocked(() -> lock.writeLock(), function);
+            return lockApplyUnlock(() -> lock.writeLock(), function);
         }
 
-        protected void acceptLocked(final LongSupplier stampSupplier, final FailableConsumer<O, ?> consumer) {
+        protected void lockAcceptUnlock(final LongSupplier stampSupplier, final FailableConsumer<O, ?> consumer) {
             final long stamp = stampSupplier.getAsLong();
             try {
                 consumer.accept(lockedObject);
@@ -105,7 +106,7 @@ protected void acceptLocked(final LongSupplier stampSupplier, final FailableCons
             }
         }
 
-        protected <T> T applyLocked(final LongSupplier stampSupplier, final FailableFunction<O, T, ?> function) {
+        protected <T> T lockApplyUnlock(final LongSupplier stampSupplier, final FailableFunction<O, T, ?> function) {
             final long stamp = stampSupplier.getAsLong();
             try {
                 return function.apply(lockedObject);

src/main/java/org/apache/commons/lang3/concurrent/TimedSemaphore.java

@@ -16,13 +16,13 @@
  */
 package org.apache.commons.lang3.concurrent;
 
-import org.apache.commons.lang3.Validate;
-
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
+import org.apache.commons.lang3.Validate;
+
 /**
  * <p>
  * A specialized <em>semaphore</em> implementation that provides a number of

src/main/java/org/apache/commons/lang3/exception/ExceptionUtils.java

@@ -24,12 +24,12 @@
 import java.lang.reflect.UndeclaredThrowableException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.StringTokenizer;
 
 import org.apache.commons.lang3.ArrayUtils;
 import org.apache.commons.lang3.ClassUtils;
 import org.apache.commons.lang3.StringUtils;
-import org.apache.commons.lang3.Validate;
 
 /**
  * <p>Provides utilities for manipulating and examining
@@ -624,20 +624,21 @@ public static void printRootCauseStackTrace(final Throwable throwable) {
      * that don't have nested causes.</p>
      *
      * @param throwable  the throwable to output, may be null
-     * @param stream  the stream to output to, may not be null
+     * @param printStream  the stream to output to, may not be null
-     * @throws IllegalArgumentException if the stream is {@code null}
+     * @throws NullPointerException if the printStream is {@code null}
      * @since 2.0
      */
-    public static void printRootCauseStackTrace(final Throwable throwable, final PrintStream stream) {
+    @SuppressWarnings("resource")
+    public static void printRootCauseStackTrace(final Throwable throwable, final PrintStream printStream) {
         if (throwable == null) {
             return;
         }
-        Validate.notNull(stream, "The PrintStream must not be null");
+        Objects.requireNonNull(printStream, "printStream");
         final String[] trace = getRootCauseStackTrace(throwable);
         for (final String element : trace) {
-            stream.println(element);
+            printStream.println(element);
         }
-        stream.flush();
+        printStream.flush();
     }
 
     /**
@@ -655,20 +656,21 @@ public static void printRootCauseStackTrace(final Throwable throwable, final Pri
      * that don't have nested causes.</p>
      *
      * @param throwable  the throwable to output, may be null
-     * @param writer  the writer to output to, may not be null
+     * @param printWriter  the writer to output to, may not be null
-     * @throws IllegalArgumentException if the writer is {@code null}
+     * @throws NullPointerException if the printWriter is {@code null}
      * @since 2.0
      */
-    public static void printRootCauseStackTrace(final Throwable throwable, final PrintWriter writer) {
+    @SuppressWarnings("resource")
+    public static void printRootCauseStackTrace(final Throwable throwable, final PrintWriter printWriter) {
         if (throwable == null) {
             return;
         }
-        Validate.notNull(writer, "The PrintWriter must not be null");
+        Objects.requireNonNull(printWriter, "printWriter");
         final String[] trace = getRootCauseStackTrace(throwable);
         for (final String element : trace) {
-            writer.println(element);
+            printWriter.println(element);
         }
-        writer.flush();
+        printWriter.flush();
     }
 
     /**

src/main/java/org/apache/commons/lang3/function/Failable.java

@@ -41,15 +41,14 @@
  * constructs like:
  *
  * <pre>
- * {@code
+ * Consumer&lt;java.lang.reflect.Method-&gt; consumer = (m) -&gt; {
- *     Consumer<java.lang.reflect.Method> consumer = (m) -> {
  *     try {
  *         m.invoke(o, args);
  *     } catch (Throwable t) {
  *         throw Failable.rethrow(t);
  *     }
  * };
- * }</pre>
+ * </pre>
  *
  * <p>
  * By replacing a {@link java.util.function.Consumer Consumer&lt;O&gt;} with a {@link FailableConsumer
@@ -57,9 +56,8 @@
  * </p>
  *
  * <pre>
- * {@code
+ * Functions.accept((m) -&gt; m.invoke(o, args));
- *   Functions.accept((m) -> m.invoke(o,args));
+ * </pre>
- * }</pre>
  *
  * <p>
  * Obviously, the second version is much more concise and the spirit of Lambda expressions is met better than the second
@@ -76,12 +74,12 @@ public class Failable {
      * @param consumer the consumer to consume
      * @param object1 the first object to consume by {@code consumer}
      * @param object2 the second object to consume by {@code consumer}
-     * @param <O1> the type of the first argument the consumer accepts
+     * @param <T> the type of the first argument the consumer accepts
-     * @param <O2> the type of the second argument the consumer accepts
+     * @param <U> the type of the second argument the consumer accepts
-     * @param <T> the type of checked exception the consumer may throw
+     * @param <E> the type of checked exception the consumer may throw
      */
-    public static <O1, O2, T extends Throwable> void accept(final FailableBiConsumer<O1, O2, T> consumer,
+    public static <T, U, E extends Throwable> void accept(final FailableBiConsumer<T, U, E> consumer, final T object1,
-        final O1 object1, final O2 object2) {
+        final U object2) {
         run(() -> consumer.accept(object1, object2));
     }
 
@@ -90,10 +88,10 @@ public static <O1, O2, T extends Throwable> void accept(final FailableBiConsumer
      *
      * @param consumer the consumer to consume
      * @param object the object to consume by {@code consumer}
-     * @param <O> the type the consumer accepts
+     * @param <T> the type the consumer accepts
-     * @param <T> the type of checked exception the consumer may throw
+     * @param <E> the type of checked exception the consumer may throw
      */
-    public static <O, T extends Throwable> void accept(final FailableConsumer<O, T> consumer, final O object) {
+    public static <T, E extends Throwable> void accept(final FailableConsumer<T, E> consumer, final T object) {
         run(() -> consumer.accept(object));
     }
 
@@ -102,9 +100,9 @@ public static <O, T extends Throwable> void accept(final FailableConsumer<O, T>
      *
      * @param consumer the consumer to consume
      * @param value the value to consume by {@code consumer}
-     * @param <T> the type of checked exception the consumer may throw
+     * @param <E> the type of checked exception the consumer may throw
      */
-    public static <T extends Throwable> void accept(final FailableDoubleConsumer<T> consumer, final double value) {
+    public static <E extends Throwable> void accept(final FailableDoubleConsumer<E> consumer, final double value) {
         run(() -> consumer.accept(value));
     }
 
@@ -113,9 +111,9 @@ public static <T extends Throwable> void accept(final FailableDoubleConsumer<T>
      *
      * @param consumer the consumer to consume
      * @param value the value to consume by {@code consumer}
-     * @param <T> the type of checked exception the consumer may throw
+     * @param <E> the type of checked exception the consumer may throw
      */
-    public static <T extends Throwable> void accept(final FailableIntConsumer<T> consumer, final int value) {
+    public static <E extends Throwable> void accept(final FailableIntConsumer<E> consumer, final int value) {
         run(() -> consumer.accept(value));
     }
 
@@ -124,9 +122,9 @@ public static <T extends Throwable> void accept(final FailableIntConsumer<T> con
      *
      * @param consumer the consumer to consume
      * @param value the value to consume by {@code consumer}
-     * @param <T> the type of checked exception the consumer may throw
+     * @param <E> the type of checked exception the consumer may throw
      */
-    public static <T extends Throwable> void accept(final FailableLongConsumer<T> consumer, final long value) {
+    public static <E extends Throwable> void accept(final FailableLongConsumer<E> consumer, final long value) {
         run(() -> consumer.accept(value));
     }
 
@@ -136,14 +134,14 @@ public static <T extends Throwable> void accept(final FailableLongConsumer<T> co
      * @param function the function to apply
      * @param input1 the first input to apply {@code function} on
      * @param input2 the second input to apply {@code function} on
-     * @param <O1> the type of the first argument the function accepts
+     * @param <T> the type of the first argument the function accepts
-     * @param <O2> the type of the second argument the function accepts
+     * @param <U> the type of the second argument the function accepts
-     * @param <O> the return type of the function
+     * @param <R> the return type of the function
-     * @param <T> the type of checked exception the function may throw
+     * @param <E> the type of checked exception the function may throw
      * @return the value returned from the function
      */
-    public static <O1, O2, O, T extends Throwable> O apply(final FailableBiFunction<O1, O2, O, T> function,
+    public static <T, U, R, E extends Throwable> R apply(final FailableBiFunction<T, U, R, E> function, final T input1,
-        final O1 input1, final O2 input2) {
+        final U input2) {
         return get(() -> function.apply(input1, input2));
     }
 
@@ -152,12 +150,12 @@ public static <O1, O2, O, T extends Throwable> O apply(final FailableBiFunction<
      *
      * @param function the function to apply
      * @param input the input to apply {@code function} on
-     * @param <I> the type of the argument the function accepts
+     * @param <T> the type of the argument the function accepts
-     * @param <O> the return type of the function
+     * @param <R> the return type of the function
-     * @param <T> the type of checked exception the function may throw
+     * @param <E> the type of checked exception the function may throw
      * @return the value returned from the function
      */
-    public static <I, O, T extends Throwable> O apply(final FailableFunction<I, O, T> function, final I input) {
+    public static <T, R, E extends Throwable> R apply(final FailableFunction<T, R, E> function, final T input) {
         return get(() -> function.apply(input));
     }
 
@@ -167,10 +165,10 @@ public static <I, O, T extends Throwable> O apply(final FailableFunction<I, O, T
      * @param function the function to apply
      * @param left the first input to apply {@code function} on
      * @param right the second input to apply {@code function} on
-     * @param <T> the type of checked exception the function may throw
+     * @param <E> the type of checked exception the function may throw
      * @return the value returned from the function
      */
-    public static <T extends Throwable> double applyAsDouble(final FailableDoubleBinaryOperator<T> function,
+    public static <E extends Throwable> double applyAsDouble(final FailableDoubleBinaryOperator<E> function,
         final double left, final double right) {
         return getAsDouble(() -> function.applyAsDouble(left, right));
     }
@@ -178,82 +176,82 @@ public static <T extends Throwable> double applyAsDouble(final FailableDoubleBin
     /**
      * Converts the given {@link FailableBiConsumer} into a standard {@link BiConsumer}.
      *
-     * @param <O1> the type of the first argument of the consumers
+     * @param <T> the type of the first argument of the consumers
-     * @param <O2> the type of the second argument of the consumers
+     * @param <U> the type of the second argument of the consumers
      * @param consumer a failable {@code BiConsumer}
      * @return a standard {@code BiConsumer}
      */
-    public static <O1, O2> BiConsumer<O1, O2> asBiConsumer(final FailableBiConsumer<O1, O2, ?> consumer) {
+    public static <T, U> BiConsumer<T, U> asBiConsumer(final FailableBiConsumer<T, U, ?> consumer) {
         return (input1, input2) -> accept(consumer, input1, input2);
     }
 
     /**
      * Converts the given {@link FailableBiFunction} into a standard {@link BiFunction}.
      *
-     * @param <O1> the type of the first argument of the input of the functions
+     * @param <T> the type of the first argument of the input of the functions
-     * @param <O2> the type of the second argument of the input of the functions
+     * @param <U> the type of the second argument of the input of the functions
-     * @param <O> the type of the output of the functions
+     * @param <R> the type of the output of the functions
      * @param function a {@code FailableBiFunction}
      * @return a standard {@code BiFunction}
      */
-    public static <O1, O2, O> BiFunction<O1, O2, O> asBiFunction(final FailableBiFunction<O1, O2, O, ?> function) {
+    public static <T, U, R> BiFunction<T, U, R> asBiFunction(final FailableBiFunction<T, U, R, ?> function) {
         return (input1, input2) -> apply(function, input1, input2);
     }
 
     /**
      * Converts the given {@link FailableBiPredicate} into a standard {@link BiPredicate}.
      *
-     * @param <O1> the type of the first argument used by the predicates
+     * @param <T> the type of the first argument used by the predicates
-     * @param <O2> the type of the second argument used by the predicates
+     * @param <U> the type of the second argument used by the predicates
      * @param predicate a {@code FailableBiPredicate}
      * @return a standard {@code BiPredicate}
      */
-    public static <O1, O2> BiPredicate<O1, O2> asBiPredicate(final FailableBiPredicate<O1, O2, ?> predicate) {
+    public static <T, U> BiPredicate<T, U> asBiPredicate(final FailableBiPredicate<T, U, ?> predicate) {
         return (input1, input2) -> test(predicate, input1, input2);
     }
 
     /**
      * Converts the given {@link FailableCallable} into a standard {@link Callable}.
      *
-     * @param <O> the type used by the callables
+     * @param <V> the type used by the callables
      * @param callable a {@code FailableCallable}
      * @return a standard {@code Callable}
      */
-    public static <O> Callable<O> asCallable(final FailableCallable<O, ?> callable) {
+    public static <V> Callable<V> asCallable(final FailableCallable<V, ?> callable) {
         return () -> call(callable);
     }
 
     /**
      * Converts the given {@link FailableConsumer} into a standard {@link Consumer}.
      *
-     * @param <I> the type used by the consumers
+     * @param <T> the type used by the consumers
      * @param consumer a {@code FailableConsumer}
      * @return a standard {@code Consumer}
      */
-    public static <I> Consumer<I> asConsumer(final FailableConsumer<I, ?> consumer) {
+    public static <T> Consumer<T> asConsumer(final FailableConsumer<T, ?> consumer) {
         return input -> accept(consumer, input);
     }
 
     /**
      * Converts the given {@link FailableFunction} into a standard {@link Function}.
      *
-     * @param <I> the type of the input of the functions
+     * @param <T> the type of the input of the functions
-     * @param <O> the type of the output of the functions
+     * @param <R> the type of the output of the functions
      * @param function a {code FailableFunction}
      * @return a standard {@code Function}
      */
-    public static <I, O> Function<I, O> asFunction(final FailableFunction<I, O, ?> function) {
+    public static <T, R> Function<T, R> asFunction(final FailableFunction<T, R, ?> function) {
         return input -> apply(function, input);
     }
 
     /**
      * Converts the given {@link FailablePredicate} into a standard {@link Predicate}.
      *
-     * @param <I> the type used by the predicates
+     * @param <T> the type used by the predicates
      * @param predicate a {@code FailablePredicate}
      * @return a standard {@code Predicate}
      */
-    public static <I> Predicate<I> asPredicate(final FailablePredicate<I, ?> predicate) {
+    public static <T> Predicate<T> asPredicate(final FailablePredicate<T, ?> predicate) {
         return input -> test(predicate, input);
     }
 
@@ -270,11 +268,11 @@ public static Runnable asRunnable(final FailableRunnable<?> runnable) {
     /**
      * Converts the given {@link FailableSupplier} into a standard {@link Supplier}.
      *
-     * @param <O> the type supplied by the suppliers
+     * @param <T> the type supplied by the suppliers
      * @param supplier a {@code FailableSupplier}
      * @return a standard {@code Supplier}
      */
-    public static <O> Supplier<O> asSupplier(final FailableSupplier<O, ?> supplier) {
+    public static <T> Supplier<T> asSupplier(final FailableSupplier<T, ?> supplier) {
         return () -> get(supplier);
     }
 
@@ -282,11 +280,11 @@ public static <O> Supplier<O> asSupplier(final FailableSupplier<O, ?> supplier)
      * Calls a callable and rethrows any exception as a {@link RuntimeException}.
      *
      * @param callable the callable to call
-     * @param <O> the return type of the callable
+     * @param <V> the return type of the callable
-     * @param <T> the type of checked exception the callable may throw
+     * @param <E> the type of checked exception the callable may throw
      * @return the value returned from the callable
      */
-    public static <O, T extends Throwable> O call(final FailableCallable<O, T> callable) {
+    public static <V, E extends Throwable> V call(final FailableCallable<V, E> callable) {
         return get(callable::call);
     }
 
@@ -294,11 +292,11 @@ public static <O, T extends Throwable> O call(final FailableCallable<O, T> calla
      * Invokes a supplier, and returns the result.
      *
      * @param supplier The supplier to invoke.
-     * @param <O> The suppliers output type.
+     * @param <T> The suppliers output type.
-     * @param <T> The type of checked exception, which the supplier can throw.
+     * @param <E> The type of checked exception, which the supplier can throw.
      * @return The object, which has been created by the supplier
      */
-    public static <O, T extends Throwable> O get(final FailableSupplier<O, T> supplier) {
+    public static <T, E extends Throwable> T get(final FailableSupplier<T, E> supplier) {
         try {
             return supplier.get();
         } catch (final Throwable t) {
@@ -310,10 +308,10 @@ public static <O, T extends Throwable> O get(final FailableSupplier<O, T> suppli
      * Invokes a boolean supplier, and returns the result.
      *
      * @param supplier The boolean supplier to invoke.
-     * @param <T> The type of checked exception, which the supplier can throw.
+     * @param <E> The type of checked exception, which the supplier can throw.
      * @return The boolean, which has been created by the supplier
      */
-    public static <T extends Throwable> boolean getAsBoolean(final FailableBooleanSupplier<T> supplier) {
+    public static <E extends Throwable> boolean getAsBoolean(final FailableBooleanSupplier<E> supplier) {
         try {
             return supplier.getAsBoolean();
         } catch (final Throwable t) {
@@ -325,10 +323,10 @@ public static <T extends Throwable> boolean getAsBoolean(final FailableBooleanSu
      * Invokes a double supplier, and returns the result.
      *
      * @param supplier The double supplier to invoke.
-     * @param <T> The type of checked exception, which the supplier can throw.
+     * @param <E> The type of checked exception, which the supplier can throw.
      * @return The boolean, which has been created by the supplier
      */
-    public static <T extends Throwable> double getAsDouble(final FailableDoubleSupplier<T> supplier) {
+    public static <E extends Throwable> double getAsDouble(final FailableDoubleSupplier<E> supplier) {
         try {
             return supplier.getAsDouble();
         } catch (final Throwable t) {
@@ -340,10 +338,10 @@ public static <T extends Throwable> double getAsDouble(final FailableDoubleSuppl
      * Invokes an int supplier, and returns the result.
      *
      * @param supplier The int supplier to invoke.
-     * @param <T> The type of checked exception, which the supplier can throw.
+     * @param <E> The type of checked exception, which the supplier can throw.
      * @return The boolean, which has been created by the supplier
      */
-    public static <T extends Throwable> int getAsInt(final FailableIntSupplier<T> supplier) {
+    public static <E extends Throwable> int getAsInt(final FailableIntSupplier<E> supplier) {
         try {
             return supplier.getAsInt();
         } catch (final Throwable t) {
@@ -355,10 +353,10 @@ public static <T extends Throwable> int getAsInt(final FailableIntSupplier<T> su
      * Invokes a long supplier, and returns the result.
      *
      * @param supplier The long supplier to invoke.
-     * @param <T> The type of checked exception, which the supplier can throw.
+     * @param <E> The type of checked exception, which the supplier can throw.
      * @return The boolean, which has been created by the supplier
      */
-    public static <T extends Throwable> long getAsLong(final FailableLongSupplier<T> supplier) {
+    public static <E extends Throwable> long getAsLong(final FailableLongSupplier<E> supplier) {
         try {
             return supplier.getAsLong();
         } catch (final Throwable t) {
@@ -410,9 +408,9 @@ public static RuntimeException rethrow(final Throwable throwable) {
      * Runs a runnable and rethrows any exception as a {@link RuntimeException}.
      *
      * @param runnable The runnable to run
-     * @param <T> the type of checked exception the runnable may throw
+     * @param <E> the type of checked exception the runnable may throw
      */
-    public static <T extends Throwable> void run(final FailableRunnable<T> runnable) {
+    public static <E extends Throwable> void run(final FailableRunnable<E> runnable) {
         try {
             runnable.run();
         } catch (final Throwable t) {
@@ -429,10 +427,10 @@ public static <T extends Throwable> void run(final FailableRunnable<T> runnable)
      * </pre>
      *
      * @param collection The collection, which is being converted into a {@link FailableStream}.
-     * @param <O> The collections element type. (In turn, the result streams element type.)
+     * @param <E> The collections element type. (In turn, the result streams element type.)
      * @return The created {@link FailableStream}.
      */
-    public static <O> FailableStream<O> stream(final Collection<O> collection) {
+    public static <E> FailableStream<E> stream(final Collection<E> collection) {
         return new FailableStream<>(collection.stream());
     }
 
@@ -443,10 +441,10 @@ public static <O> FailableStream<O> stream(final Collection<O> collection) {
      * {@link Function}, {@link Consumer}, etc.
      *
      * @param stream The stream, which is being converted into a {@link FailableStream}.
-     * @param <O> The streams element type.
+     * @param <T> The streams element type.
      * @return The created {@link FailableStream}.
      */
-    public static <O> FailableStream<O> stream(final Stream<O> stream) {
+    public static <T> FailableStream<T> stream(final Stream<T> stream) {
         return new FailableStream<>(stream);
     }
 
@@ -456,14 +454,14 @@ public static <O> FailableStream<O> stream(final Stream<O> stream) {
      * @param predicate the predicate to test
      * @param object1 the first input to test by {@code predicate}
      * @param object2 the second input to test by {@code predicate}
-     * @param <O1> the type of the first argument the predicate tests
+     * @param <T> the type of the first argument the predicate tests
-     * @param <O2> the type of the second argument the predicate tests
+     * @param <U> the type of the second argument the predicate tests
-     * @param <T> the type of checked exception the predicate may throw
+     * @param <E> the type of checked exception the predicate may throw
      * @return the boolean value returned by the predicate
      */
-    public static <O1, O2, T extends Throwable> boolean test(final FailableBiPredicate<O1, O2, T> predicate,
+    public static <T, U, E extends Throwable> boolean test(final FailableBiPredicate<T, U, E> predicate,
-        final O1 object1, final O2 object2) {
+        final T object1, final U object2) {
-        return get(() -> predicate.test(object1, object2));
+        return getAsBoolean(() -> predicate.test(object1, object2));
     }
 
     /**
@@ -471,12 +469,12 @@ public static <O1, O2, T extends Throwable> boolean test(final FailableBiPredica
      *
      * @param predicate the predicate to test
      * @param object the input to test by {@code predicate}
-     * @param <O> the type of argument the predicate tests
+     * @param <T> the type of argument the predicate tests
-     * @param <T> the type of checked exception the predicate may throw
+     * @param <E> the type of checked exception the predicate may throw
      * @return the boolean value returned by the predicate
      */
-    public static <O, T extends Throwable> boolean test(final FailablePredicate<O, T> predicate, final O object) {
+    public static <T, E extends Throwable> boolean test(final FailablePredicate<T, E> predicate, final T object) {
-        return get(() -> predicate.test(object));
+        return getAsBoolean(() -> predicate.test(object));
     }
 
     /**
@@ -487,10 +485,8 @@ public static <O, T extends Throwable> boolean test(final FailablePredicate<O, T
      * {@link Throwable} is rethrown. Example use:
      *
      * <pre>
-     *     {@code
      * final FileInputStream fis = new FileInputStream("my.file");
-     *     Functions.tryWithResources(useInputStream(fis), null, () -> fis.close());
+     * Functions.tryWithResources(useInputStream(fis), null, () -&gt; fis.close());
-     * }
      * </pre>
      *
      * @param action The action to execute. This object <em>will</em> always be invoked.
@@ -549,10 +545,8 @@ public static void tryWithResources(final FailableRunnable<? extends Throwable>
      * {@link Throwable} is rethrown. Example use:
      *
      * <pre>
-     *     {@code
      * final FileInputStream fis = new FileInputStream("my.file");
-     *     Functions.tryWithResources(useInputStream(fis), () -> fis.close());
+     * Functions.tryWithResources(useInputStream(fis), () -&gt; fis.close());
-     * }
      * </pre>
      *
      * @param action The action to execute. This object <em>will</em> always be invoked.

src/main/java/org/apache/commons/lang3/function/FailableBiConsumer.java

@@ -17,25 +17,57 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.BiConsumer;
 
 /**
  * A functional interface like {@link BiConsumer} that declares a {@code Throwable}.
  *
- * @param <O1> Consumed type 1.
+ * @param <T> Consumed type 1.
- * @param <O2> Consumed type 2.
+ * @param <U> Consumed type 2.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableBiConsumer<O1, O2, T extends Throwable> {
+public interface FailableBiConsumer<T, U, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableBiConsumer NOP = (t, u) -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> Consumed type 1.
+     * @param <U> Consumed type 2.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, U, E extends Throwable> FailableBiConsumer<T, U, E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
-     * @param object1 the first parameter for the consumable to accept
+     * @param t the first parameter for the consumable to accept
-     * @param object2 the second parameter for the consumable to accept
+     * @param u the second parameter for the consumable to accept
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(O1 object1, O2 object2) throws T;
+    void accept(T t, U u) throws E;
+
+    /**
+     * Returns a composed {@code FailableBiConsumer} like {@link BiConsumer#andThen(BiConsumer)}.
+     *
+     * @param after the operation to perform after this one.
+     * @return a composed {@code FailableBiConsumer} like {@link BiConsumer#andThen(BiConsumer)}.
+     * @throws NullPointerException when {@code after} is null.
+     */
+    default FailableBiConsumer<T, U, E> andThen(final FailableBiConsumer<? super T, ? super U, E> after) {
+        Objects.requireNonNull(after);
+        return (t, u) -> {
+            accept(t, u);
+            after.accept(t, u);
+        };
+    }
 }

src/main/java/org/apache/commons/lang3/function/FailableBiFunction.java

@@ -17,19 +17,51 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.BiFunction;
+import java.util.function.Function;
 
 /**
  * A functional interface like {@link BiFunction} that declares a {@code Throwable}.
  *
- * @param <O1> Input type 1.
+ * @param <T> Input type 1.
- * @param <O2> Input type 2.
+ * @param <U> Input type 2.
  * @param <R> Return type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableBiFunction<O1, O2, R, T extends Throwable> {
+public interface FailableBiFunction<T, U, R, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableBiFunction NOP = (t, u) -> null;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> Consumed type 1.
+     * @param <U> Consumed type 2.
+     * @param <R> Return type.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, U, R, E extends Throwable> FailableBiFunction<T, U, R, E> nop() {
+        return NOP;
+    }
+
+    /**
+     * Returns a composed {@code FailableBiFunction} that like {@link BiFunction#andThen(Function)}.
+     *
+     * @param <V> the output type of the {@code after} function, and of the composed function.
+     * @param after the operation to perform after this one.
+     * @return a composed {@code FailableBiFunction} that like {@link BiFunction#andThen(Function)}.
+     * @throws NullPointerException when {@code after} is null.
+     */
+    default <V> FailableBiFunction<T, U, V, E> andThen(final FailableFunction<? super R, ? extends V, E> after) {
+        Objects.requireNonNull(after);
+        return (final T t, final U u) -> after.apply(apply(t, u));
+    }
 
     /**
      * Applies this function.
@@ -37,7 +69,7 @@ public interface FailableBiFunction<O1, O2, R, T extends Throwable> {
      * @param input1 the first input for the function
      * @param input2 the second input for the function
      * @return the result of the function
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    R apply(O1 input1, O2 input2) throws T;
+    R apply(T input1, U input2) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableBiPredicate.java

@@ -17,18 +17,84 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.BiPredicate;
 
 /**
  * A functional interface like {@link BiPredicate} that declares a {@code Throwable}.
  *
- * @param <O1> Predicate type 1.
+ * @param <T> Predicate type 1.
- * @param <O2> Predicate type 2.
+ * @param <U> Predicate type 2.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableBiPredicate<O1, O2, T extends Throwable> {
+public interface FailableBiPredicate<T, U, E extends Throwable> {
+
+    /** FALSE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableBiPredicate FALSE = (t, u) -> false;
+
+    /** TRUE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableBiPredicate TRUE = (t, u) -> true;
+
+    /**
+     * Returns The FALSE singleton.
+     *
+     * @param <T> Consumed type 1.
+     * @param <U> Consumed type 2.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, U, E extends Throwable> FailableBiPredicate<T, U, E> falsePredicate() {
+        return FALSE;
+    }
+
+    /**
+     * Returns The FALSE TRUE.
+     *
+     * @param <T> Consumed type 1.
+     * @param <U> Consumed type 2.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, U, E extends Throwable> FailableBiPredicate<T, U, E> truePredicate() {
+        return TRUE;
+    }
+
+    /**
+     * Returns a composed {@code FailableBiPredicate} like {@link BiPredicate#and(BiPredicate)}.
+     *
+     * @param other a predicate that will be logically-ANDed with this predicate.
+     * @return a composed {@code FailableBiPredicate} like {@link BiPredicate#and(BiPredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableBiPredicate<T, U, E> and(final FailableBiPredicate<? super T, ? super U, E> other) {
+        Objects.requireNonNull(other);
+        return (final T t, final U u) -> test(t, u) && other.test(t, u);
+    }
+
+    /**
+     * Returns a predicate that negates this predicate.
+     *
+     * @return a predicate that negates this predicate.
+     */
+    default FailableBiPredicate<T, U, E> negate() {
+        return (final T t, final U u) -> !test(t, u);
+    }
+
+    /**
+     * Returns a composed {@code FailableBiPredicate} like {@link BiPredicate#and(BiPredicate)}.
+     *
+     * @param other a predicate that will be logically-ORed with this predicate.
+     * @return a composed {@code FailableBiPredicate} like {@link BiPredicate#and(BiPredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableBiPredicate<T, U, E> or(final FailableBiPredicate<? super T, ? super U, E> other) {
+        Objects.requireNonNull(other);
+        return (final T t, final U u) -> test(t, u) || other.test(t, u);
+    }
 
     /**
      * Tests the predicate.
@@ -36,7 +102,7 @@ public interface FailableBiPredicate<O1, O2, T extends Throwable> {
      * @param object1 the first object to test the predicate on
      * @param object2 the second object to test the predicate on
      * @return the predicate's evaluation
-     * @throws T if the predicate fails
+     * @throws E Thrown when this predicate fails.
      */
-    boolean test(O1 object1, O2 object2) throws T;
+    boolean test(T object1, U object2) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableBooleanSupplier.java

@@ -22,17 +22,17 @@
 /**
  * A functional interface like {@link BooleanSupplier} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableBooleanSupplier<T extends Throwable> {
+public interface FailableBooleanSupplier<E extends Throwable> {
 
     /**
      * Supplies a boolean.
      *
      * @return a result
-     * @throws T if the supplier fails
+     * @throws E if the supplier fails
      */
-    boolean getAsBoolean() throws T;
+    boolean getAsBoolean() throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableCallable.java

@@ -21,17 +21,17 @@
  * A functional interface like {@link java.util.concurrent.Callable} that declares a {@code Throwable}.
  *
  * @param <R> Return type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableCallable<R, T extends Throwable> {
+public interface FailableCallable<R, E extends Throwable> {
 
     /**
      * Calls the callable.
      *
      * @return The value returned from the callable
-     * @throws T if the callable fails
+     * @throws E if the callable fails
      */
-    R call() throws T;
+    R call() throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableConsumer.java

@@ -17,23 +17,54 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.Consumer;
 
 /**
  * A functional interface like {@link Consumer} that declares a {@code Throwable}.
  *
- * @param <O> Consumed type 1.
+ * @param <T> Consumed type 1.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableConsumer<O, T extends Throwable> {
+public interface FailableConsumer<T, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableConsumer NOP = t -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> Consumed type 1.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailableConsumer<T, E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
      * @param object the parameter for the consumable to accept
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(O object) throws T;
+    void accept(T object) throws E;
+
+    /**
+     * Returns a composed {@code Consumer} like {@link Consumer#andThen(Consumer)}.
+     *
+     * @param after the operation to perform after this operation
+     * @return a composed {@code Consumer} like {@link Consumer#andThen(Consumer)}.
+     * @throws NullPointerException when {@code after} is null
+     */
+    default FailableConsumer<T, E> andThen(final FailableConsumer<? super T, E> after) {
+        Objects.requireNonNull(after);
+        return (final T t) -> {
+            accept(t);
+            after.accept(t);
+        };
+    }
 }

src/main/java/org/apache/commons/lang3/function/FailableDoubleBinaryOperator.java

@@ -22,11 +22,11 @@
 /**
  * A functional interface like {@link DoubleBinaryOperator} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableDoubleBinaryOperator<T extends Throwable> {
+public interface FailableDoubleBinaryOperator<E extends Throwable> {
 
     /**
      * Applies this operator to the given operands.
@@ -34,7 +34,7 @@ public interface FailableDoubleBinaryOperator<T extends Throwable> {
      * @param left the first operand
      * @param right the second operand
      * @return the operator result
-     * @throws T if the operation fails
+     * @throws E if the operation fails
      */
-    double applyAsDouble(double left, double right) throws T;
+    double applyAsDouble(double left, double right) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableDoubleConsumer.java

@@ -17,22 +17,52 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.DoubleConsumer;
 
 /**
  * A functional interface like {@link DoubleConsumer} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableDoubleConsumer<T extends Throwable> {
+public interface FailableDoubleConsumer<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableDoubleConsumer NOP = t -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableDoubleConsumer<E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
      * @param value the parameter for the consumable to accept
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(double value) throws T;
+    void accept(double value) throws E;
+
+    /**
+     * Returns a composed {@code FailableDoubleConsumer} like {@link DoubleConsumer#andThen(DoubleConsumer)}.
+     *
+     * @param after the operation to perform after this one.
+     * @return a composed {@code FailableDoubleConsumer} like {@link DoubleConsumer#andThen(DoubleConsumer)}.
+     * @throws NullPointerException when {@code after} is null.
+     */
+    default FailableDoubleConsumer<E> andThen(final FailableDoubleConsumer<E> after) {
+        Objects.requireNonNull(after);
+        return (final double t) -> {
+            accept(t);
+            after.accept(t);
+        };
+    }
 }

src/main/java/org/apache/commons/lang3/function/FailableDoubleFunction.java

@@ -23,18 +23,33 @@
  * A functional interface like {@link DoubleFunction} that declares a {@code Throwable}.
  *
  * @param <R> Return type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableDoubleFunction<R, T extends Throwable> {
+public interface FailableDoubleFunction<R, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableDoubleFunction NOP = t -> null;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <R> Return type.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <R, E extends Throwable> FailableDoubleFunction<R, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function.
      *
      * @param input the input for the function
      * @return the result of the function
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    R apply(double input) throws T;
+    R apply(double input) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableDoublePredicate.java

@@ -17,23 +17,85 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.DoublePredicate;
 
 /**
  * A functional interface like {@link DoublePredicate} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableDoublePredicate<T extends Throwable> {
+public interface FailableDoublePredicate<E extends Throwable> {
+
+    /** FALSE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableDoublePredicate FALSE = t -> false;
+
+    /** TRUE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableDoublePredicate TRUE = t -> true;
+
+    /**
+     * Returns The FALSE singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableDoublePredicate<E> falsePredicate() {
+        return FALSE;
+    }
+
+    /**
+     * Returns The FALSE TRUE.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableDoublePredicate<E> truePredicate() {
+        return TRUE;
+    }
+
+    /**
+     * Returns a composed {@code FailableDoublePredicate} like {@link DoublePredicate#and(DoublePredicate)}.
+     *
+     * @param other a predicate that will be logically-ANDed with this predicate.
+     * @return a composed {@code FailableDoublePredicate} like {@link DoublePredicate#and(DoublePredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableDoublePredicate<E> and(final FailableDoublePredicate<E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) && other.test(t);
+    }
+
+    /**
+     * Returns a predicate that negates this predicate.
+     *
+     * @return a predicate that negates this predicate.
+     */
+    default FailableDoublePredicate<E> negate() {
+        return t -> !test(t);
+    }
+
+    /**
+     * Returns a composed {@code FailableDoublePredicate} like {@link DoublePredicate#and(DoublePredicate)}.
+     *
+     * @param other a predicate that will be logically-ORed with this predicate.
+     * @return a composed {@code FailableDoublePredicate} like {@link DoublePredicate#and(DoublePredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableDoublePredicate<E> or(final FailableDoublePredicate<E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) || other.test(t);
+    }
 
     /**
      * Tests the predicate.
      *
      * @param value the parameter for the predicate to accept.
      * @return {@code true} if the input argument matches the predicate, {@code false} otherwise.
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    boolean test(double value) throws T;
+    boolean test(double value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableDoubleSupplier.java

@@ -22,17 +22,17 @@
 /**
  * A functional interface like {@link DoubleSupplier} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableDoubleSupplier<T extends Throwable> {
+public interface FailableDoubleSupplier<E extends Throwable> {
 
     /**
      * Supplies a double.
      *
      * @return a result
-     * @throws T if the supplier fails
+     * @throws E if the supplier fails
      */
-    double getAsDouble() throws T;
+    double getAsDouble() throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableDoubleToIntFunction.java

@@ -22,18 +22,32 @@
 /**
  * A functional interface like {@link DoubleToIntFunction} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableDoubleToIntFunction<T extends Throwable> {
+public interface FailableDoubleToIntFunction<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableDoubleToIntFunction NOP = t -> 0;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableDoubleToIntFunction<E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given argument.
      *
      * @param value the function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    int applyAsInt(double value) throws T;
+    int applyAsInt(double value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableDoubleToLongFunction.java

@@ -22,18 +22,32 @@
 /**
  * A functional interface like {@link DoubleToLongFunction} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableDoubleToLongFunction<T extends Throwable> {
+public interface FailableDoubleToLongFunction<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableDoubleToLongFunction NOP = t -> 0;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableDoubleToLongFunction<E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given argument.
      *
      * @param value the function argument
      * @return the function result
-     * @throws T if the operation fails
+     * @throws E if the operation fails
      */
-    int applyAsLong(double value) throws T;
+    int applyAsLong(double value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableDoubleUnaryOperator.java

@@ -0,0 +1,93 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.lang3.function;
+
+import java.util.Objects;
+import java.util.function.DoubleUnaryOperator;
+
+/**
+ * A functional interface like {@link DoubleUnaryOperator} that declares a {@code Throwable}.
+ *
+ * @param <E> Thrown exception.
+ * @since 3.11
+ */
+public interface FailableDoubleUnaryOperator<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableDoubleUnaryOperator NOP = t -> 0d;
+
+    /**
+     * Returns a unary operator that always returns its input argument.
+     *
+     * @param <E> Thrown exception.
+     * @return a unary operator that always returns its input argument
+     */
+    static <E extends Throwable> FailableDoubleUnaryOperator<E> identity() {
+        return t -> t;
+    }
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableDoubleUnaryOperator<E> nop() {
+        return NOP;
+    }
+
+    /**
+     * Returns a composed {@code FailableDoubleUnaryOperator} like
+     * {@link DoubleUnaryOperator#andThen(DoubleUnaryOperator)}.
+     *
+     * @param after the operator to apply after this one.
+     * @return a composed {@code FailableDoubleUnaryOperator} like
+     *         {@link DoubleUnaryOperator#andThen(DoubleUnaryOperator)}.
+     * @throws NullPointerException if after is null.
+     * @see #compose(FailableDoubleUnaryOperator)
+     */
+    default FailableDoubleUnaryOperator<E> andThen(final FailableDoubleUnaryOperator<E> after) {
+        Objects.requireNonNull(after);
+        return (final double t) -> after.applyAsDouble(applyAsDouble(t));
+    }
+
+    /**
+     * Applies this operator to the given operand.
+     *
+     * @param operand the operand
+     * @return the operator result
+     * @throws E Thrown when a consumer fails.
+     */
+    double applyAsDouble(double operand) throws E;
+
+    /**
+     * Returns a composed {@code FailableDoubleUnaryOperator} like
+     * {@link DoubleUnaryOperator#compose(DoubleUnaryOperator)}.
+     *
+     * @param before the operator to apply before this one.
+     * @return a composed {@code FailableDoubleUnaryOperator} like
+     *         {@link DoubleUnaryOperator#compose(DoubleUnaryOperator)}.
+     * @throws NullPointerException if before is null.
+     * @see #andThen(FailableDoubleUnaryOperator)
+     */
+    default FailableDoubleUnaryOperator<E> compose(final FailableDoubleUnaryOperator<E> before) {
+        Objects.requireNonNull(before);
+        return (final double v) -> applyAsDouble(before.applyAsDouble(v));
+    }
+}

src/main/java/org/apache/commons/lang3/function/FailableFunction.java

@@ -17,25 +17,80 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.Function;
 
 /**
  * A functional interface like {@link Function} that declares a {@code Throwable}.
  *
- * @param <I> Input type 1.
+ * @param <T> Input type 1.
  * @param <R> Return type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableFunction<I, R, T extends Throwable> {
+public interface FailableFunction<T, R, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableFunction NOP = t -> null;
+
+    /**
+     * Returns a function that always returns its input argument.
+     *
+     * @param <T> the type of the input and output objects to the function
+     * @param <E> Thrown exception.
+     * @return a function that always returns its input argument
+     */
+    static <T, E extends Throwable> FailableFunction<T, T, E> identity() {
+        return t -> t;
+    }
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> Consumed type 1.
+     * @param <R> Return type.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, R, E extends Throwable> FailableFunction<T, R, E> nop() {
+        return NOP;
+    }
+
+    /**
+     * Returns a composed {@code FailableFunction} like {@link Function#andThen(Function)}.
+     *
+     * @param <V> the output type of the {@code after} function, and of the composed function.
+     * @return a composed {@code FailableFunction} like {@link Function#andThen(Function)}.
+     * @param after the operation to perform after this one.
+     * @throws NullPointerException when {@code after} is null.
+     */
+    default <V> FailableFunction<T, V, E> andThen(final FailableFunction<? super R, ? extends V, E> after) {
+        Objects.requireNonNull(after);
+        return (final T t) -> after.apply(apply(t));
+    }
 
     /**
      * Applies this function.
      *
      * @param input the input for the function
      * @return the result of the function
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    R apply(I input) throws T;
+    R apply(T input) throws E;
+
+    /**
+     * Returns a composed {@code FailableFunction} like {@link Function#compose(Function)}.
+     *
+     * @param <V> the input type to the {@code before} function, and to the composed function.
+     * @param before the operator to apply before this one.
+     * @return a a composed {@code FailableFunction} like {@link Function#compose(Function)}.
+     * @throws NullPointerException if before is null.
+     * @see #andThen(FailableFunction)
+     */
+    default <V> FailableFunction<V, R, E> compose(final FailableFunction<? super V, ? extends T, E> before) {
+        Objects.requireNonNull(before);
+        return (final V v) -> apply(before.apply(v));
+    }
 }

src/main/java/org/apache/commons/lang3/function/FailableIntBinaryOperator.java

@@ -22,11 +22,11 @@
 /**
  * A functional interface like {@link IntBinaryOperator} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableIntBinaryOperator<T extends Throwable> {
+public interface FailableIntBinaryOperator<E extends Throwable> {
 
     /**
      * Applies this operator to the given operands.
@@ -34,7 +34,7 @@ public interface FailableIntBinaryOperator<T extends Throwable> {
      * @param left the first operand
      * @param right the second operand
      * @return the operator result
-     * @throws T if the operation fails
+     * @throws E if the operation fails
      */
-    int applyAsInt(int left, int right) throws T;
+    int applyAsInt(int left, int right) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableIntConsumer.java

@@ -17,22 +17,53 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.IntConsumer;
 
 /**
  * A functional interface like {@link IntConsumer} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableIntConsumer<T extends Throwable> {
+public interface FailableIntConsumer<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableIntConsumer NOP = t -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableIntConsumer<E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
      * @param value the parameter for the consumable to accept
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(int value) throws T;
+    void accept(int value) throws E;
+
+    /**
+     * Returns a composed {@code FailableIntConsumer} like {@link IntConsumer#andThen(IntConsumer)}.
+     *
+     * @param after the operation to perform after this one.
+     * @return a composed {@code FailableLongConsumer} like {@link IntConsumer#andThen(IntConsumer)}.
+     * @throws NullPointerException if {@code after} is null
+     */
+    default FailableIntConsumer<E> andThen(final FailableIntConsumer<E> after) {
+        Objects.requireNonNull(after);
+        return (final int t) -> {
+            accept(t);
+            after.accept(t);
+        };
+    }
+
 }

src/main/java/org/apache/commons/lang3/function/FailableIntFunction.java

@@ -23,18 +23,33 @@
  * A functional interface like {@link IntFunction} that declares a {@code Throwable}.
  *
  * @param <R> Return type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableIntFunction<R, T extends Throwable> {
+public interface FailableIntFunction<R, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableIntFunction NOP = t -> null;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <R> Return type.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <R, E extends Throwable> FailableIntFunction<R, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function.
      *
      * @param input the input for the function
      * @return the result of the function
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    R apply(int input) throws T;
+    R apply(int input) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableIntPredicate.java

@@ -17,23 +17,85 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.IntPredicate;
 
 /**
  * A functional interface like {@link IntPredicate} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableIntPredicate<T extends Throwable> {
+public interface FailableIntPredicate<E extends Throwable> {
+
+    /** FALSE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableIntPredicate FALSE = t -> false;
+
+    /** TRUE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableIntPredicate TRUE = t -> true;
+
+    /**
+     * Returns The FALSE singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableIntPredicate<E> falsePredicate() {
+        return FALSE;
+    }
+
+    /**
+     * Returns The FALSE TRUE.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableIntPredicate<E> truePredicate() {
+        return TRUE;
+    }
+
+    /**
+     * Returns a composed {@code FailableIntPredicate} like {@link IntPredicate#and(IntPredicate)}.
+     *
+     * @param other a predicate that will be logically-ANDed with this predicate.
+     * @return a composed {@code FailableIntPredicate} like {@link IntPredicate#and(IntPredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableIntPredicate<E> and(final FailableIntPredicate<E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) && other.test(t);
+    }
+
+    /**
+     * Returns a predicate that negates this predicate.
+     *
+     * @return a predicate that negates this predicate.
+     */
+    default FailableIntPredicate<E> negate() {
+        return t -> !test(t);
+    }
+
+    /**
+     * Returns a composed {@code FailableIntPredicate} like {@link IntPredicate#and(IntPredicate)}.
+     *
+     * @param other a predicate that will be logically-ORed with this predicate.
+     * @return a composed {@code FailableIntPredicate} like {@link IntPredicate#and(IntPredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableIntPredicate<E> or(final FailableIntPredicate<E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) || other.test(t);
+    }
 
     /**
      * Tests the predicate.
      *
      * @param value the parameter for the predicate to accept.
      * @return {@code true} if the input argument matches the predicate, {@code false} otherwise.
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    boolean test(int value) throws T;
+    boolean test(int value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableIntSupplier.java

@@ -22,17 +22,17 @@
 /**
  * A functional interface like {@link IntSupplier} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableIntSupplier<T extends Throwable> {
+public interface FailableIntSupplier<E extends Throwable> {
 
     /**
      * Supplies an int.
      *
      * @return a result
-     * @throws T if the supplier fails
+     * @throws E if the supplier fails
      */
-    int getAsInt() throws T;
+    int getAsInt() throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableIntToDoubleFunction.java

@@ -22,18 +22,32 @@
 /**
  * A functional interface like {@link IntToDoubleFunction} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableIntToDoubleFunction<T extends Throwable> {
+public interface FailableIntToDoubleFunction<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableIntToDoubleFunction NOP = t -> 0d;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableIntToDoubleFunction<E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given argument.
      *
      * @param value the function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    double applyAsDouble(int value) throws T;
+    double applyAsDouble(int value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableIntToLongFunction.java

@@ -22,18 +22,32 @@
 /**
  * A functional interface like {@link IntToLongFunction} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableIntToLongFunction<T extends Throwable> {
+public interface FailableIntToLongFunction<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableIntToLongFunction NOP = t -> 0L;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableIntToLongFunction<E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given argument.
      *
      * @param value the function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    long applyAsLong(int value) throws T;
+    long applyAsLong(int value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableIntUnaryOperator.java

@@ -0,0 +1,89 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.lang3.function;
+
+import java.util.Objects;
+import java.util.function.IntUnaryOperator;
+
+/**
+ * A functional interface like {@link IntUnaryOperator} that declares a {@code Throwable}.
+ *
+ * @param <E> Thrown exception.
+ * @since 3.11
+ */
+public interface FailableIntUnaryOperator<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableIntUnaryOperator NOP = t -> 0;
+
+    /**
+     * Returns a unary operator that always returns its input argument.
+     *
+     * @param <E> Thrown exception.
+     * @return a unary operator that always returns its input argument
+     */
+    static <E extends Throwable> FailableIntUnaryOperator<E> identity() {
+        return t -> t;
+    }
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableIntUnaryOperator<E> nop() {
+        return NOP;
+    }
+
+    /**
+     * Returns a composed {@code FailableDoubleUnaryOperator} like {@link IntUnaryOperator#andThen(IntUnaryOperator)}.
+     *
+     * @param after the operator to apply after this one.
+     * @return a composed {@code FailableIntUnaryOperator} like {@link IntUnaryOperator#andThen(IntUnaryOperator)}.
+     * @throws NullPointerException if after is null.
+     * @see #compose(FailableIntUnaryOperator)
+     */
+    default FailableIntUnaryOperator<E> andThen(final FailableIntUnaryOperator<E> after) {
+        Objects.requireNonNull(after);
+        return (final int t) -> after.applyAsInt(applyAsInt(t));
+    }
+
+    /**
+     * Applies this operator to the given operand.
+     *
+     * @param operand the operand
+     * @return the operator result
+     * @throws E Thrown when a consumer fails.
+     */
+    int applyAsInt(int operand) throws E;
+
+    /**
+     * Returns a composed {@code FailableIntUnaryOperator} like {@link IntUnaryOperator#compose(IntUnaryOperator)}.
+     *
+     * @param before the operator to apply before this one.
+     * @return a composed {@code FailableIntUnaryOperator} like {@link IntUnaryOperator#compose(IntUnaryOperator)}.
+     * @throws NullPointerException if before is null.
+     * @see #andThen(FailableIntUnaryOperator)
+     */
+    default FailableIntUnaryOperator<E> compose(final FailableIntUnaryOperator<E> before) {
+        Objects.requireNonNull(before);
+        return (final int v) -> applyAsInt(before.applyAsInt(v));
+    }
+}

src/main/java/org/apache/commons/lang3/function/FailableLongBinaryOperator.java

@@ -22,11 +22,11 @@
 /**
  * A functional interface like {@link LongBinaryOperator} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableLongBinaryOperator<T extends Throwable> {
+public interface FailableLongBinaryOperator<E extends Throwable> {
 
     /**
      * Applies this operator to the given operands.
@@ -34,7 +34,7 @@ public interface FailableLongBinaryOperator<T extends Throwable> {
      * @param left the first operand
      * @param right the second operand
      * @return the operator result
-     * @throws T if the operation fails
+     * @throws E if the operation fails
      */
-    long applyAsLong(long left, long right) throws T;
+    long applyAsLong(long left, long right) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableLongConsumer.java

@@ -17,22 +17,52 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.LongConsumer;
 
 /**
  * A functional interface like {@link LongConsumer} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableLongConsumer<T extends Throwable> {
+public interface FailableLongConsumer<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableLongConsumer NOP = t -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableLongConsumer<E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
      * @param object the parameter for the consumable to accept
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(long object) throws T;
+    void accept(long object) throws E;
+
+    /**
+     * Returns a composed {@code FailableLongConsumer} like {@link LongConsumer#andThen(LongConsumer)}.
+     *
+     * @param after the operation to perform after this one.
+     * @return a composed {@code FailableLongConsumer} like {@link LongConsumer#andThen(LongConsumer)}.
+     * @throws NullPointerException if {@code after} is null
+     */
+    default FailableLongConsumer<E> andThen(final FailableLongConsumer<E> after) {
+        Objects.requireNonNull(after);
+        return (final long t) -> {
+            accept(t);
+            after.accept(t);
+        };
+    }
 }

src/main/java/org/apache/commons/lang3/function/FailableLongFunction.java

@@ -23,18 +23,33 @@
  * A functional interface like {@link LongFunction} that declares a {@code Throwable}.
  *
  * @param <R> Return type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableLongFunction<R, T extends Throwable> {
+public interface FailableLongFunction<R, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableLongFunction NOP = t -> null;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <R> Return type.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <R, E extends Throwable> FailableLongFunction<R, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function.
      *
      * @param input the input for the function
      * @return the result of the function
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    R apply(long input) throws T;
+    R apply(long input) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableLongPredicate.java

@@ -17,23 +17,85 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.LongPredicate;
 
 /**
  * A functional interface like {@link LongPredicate} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableLongPredicate<T extends Throwable> {
+public interface FailableLongPredicate<E extends Throwable> {
+
+    /** FALSE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableLongPredicate FALSE = t -> false;
+
+    /** TRUE singleton */
+    @SuppressWarnings("rawtypes")
+    FailableLongPredicate TRUE = t -> true;
+
+    /**
+     * Returns The FALSE singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableLongPredicate<E> falsePredicate() {
+        return FALSE;
+    }
+
+    /**
+     * Returns The FALSE TRUE.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableLongPredicate<E> truePredicate() {
+        return TRUE;
+    }
+
+    /**
+     * Returns a composed {@code FailableLongPredicate} like {@link LongPredicate#and(LongPredicate)}.
+     *
+     * @param other a predicate that will be logically-ANDed with this predicate.
+     * @return a composed {@code FailableLongPredicate} like {@link LongPredicate#and(LongPredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableLongPredicate<E> and(final FailableLongPredicate<E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) && other.test(t);
+    }
+
+    /**
+     * Returns a predicate that negates this predicate.
+     *
+     * @return a predicate that negates this predicate.
+     */
+    default FailableLongPredicate<E> negate() {
+        return t -> !test(t);
+    }
+
+    /**
+     * Returns a composed {@code FailableLongPredicate} like {@link LongPredicate#and(LongPredicate)}.
+     *
+     * @param other a predicate that will be logically-ORed with this predicate.
+     * @return a composed {@code FailableLongPredicate} like {@link LongPredicate#and(LongPredicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailableLongPredicate<E> or(final FailableLongPredicate<E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) || other.test(t);
+    }
 
     /**
      * Tests the predicate.
      *
      * @param value the parameter for the predicate to accept.
      * @return {@code true} if the input argument matches the predicate, {@code false} otherwise.
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    boolean test(long value) throws T;
+    boolean test(long value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableLongSupplier.java

@@ -22,17 +22,17 @@
 /**
  * A functional interface like {@link LongSupplier} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableLongSupplier<T extends Throwable> {
+public interface FailableLongSupplier<E extends Throwable> {
 
     /**
      * Supplies a long.
      *
      * @return a result
-     * @throws T if the supplier fails
+     * @throws E if the supplier fails
      */
-    long getAsLong() throws T;
+    long getAsLong() throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableLongToDoubleFunction.java

@@ -22,18 +22,32 @@
 /**
  * A functional interface like {@link LongToDoubleFunction} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableLongToDoubleFunction<T extends Throwable> {
+public interface FailableLongToDoubleFunction<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableLongToDoubleFunction NOP = t -> 0d;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableLongToDoubleFunction<E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given argument.
      *
      * @param value the function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    double applyAsDouble(long value) throws T;
+    double applyAsDouble(long value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableLongToIntFunction.java

@@ -22,18 +22,32 @@
 /**
  * A functional interface like {@link LongToIntFunction} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableLongToIntFunction<T extends Throwable> {
+public interface FailableLongToIntFunction<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableLongToIntFunction NOP = t -> 0;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableLongToIntFunction<E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given argument.
      *
      * @param value the function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    int applyAsInt(long value) throws T;
+    int applyAsInt(long value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableLongUnaryOperator.java

@@ -0,0 +1,89 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.lang3.function;
+
+import java.util.Objects;
+import java.util.function.LongUnaryOperator;
+
+/**
+ * A functional interface like {@link LongUnaryOperator} that declares a {@code Throwable}.
+ *
+ * @param <E> Thrown exception.
+ * @since 3.11
+ */
+public interface FailableLongUnaryOperator<E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableLongUnaryOperator NOP = t -> 0L;
+
+    /**
+     * Returns a unary operator that always returns its input argument.
+     *
+     * @param <E> Thrown exception.
+     * @return a unary operator that always returns its input argument
+     */
+    static <E extends Throwable> FailableLongUnaryOperator<E> identity() {
+        return t -> t;
+    }
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <E extends Throwable> FailableLongUnaryOperator<E> nop() {
+        return NOP;
+    }
+
+    /**
+     * Returns a composed {@code FailableDoubleUnaryOperator} like {@link LongUnaryOperator#andThen(LongUnaryOperator)}.
+     *
+     * @param after the operator to apply after this one.
+     * @return a composed {@code FailableLongUnaryOperator} like {@link LongUnaryOperator#andThen(LongUnaryOperator)}.
+     * @throws NullPointerException if after is null.
+     * @see #compose(FailableLongUnaryOperator)
+     */
+    default FailableLongUnaryOperator<E> andThen(final FailableLongUnaryOperator<E> after) {
+        Objects.requireNonNull(after);
+        return (final long t) -> after.applyAsLong(applyAsLong(t));
+    }
+
+    /**
+     * Applies this operator to the given operand.
+     *
+     * @param operand the operand
+     * @return the operator result
+     * @throws E Thrown when a consumer fails.
+     */
+    long applyAsLong(long operand) throws E;
+
+    /**
+     * Returns a composed {@code FailableLongUnaryOperator} like {@link LongUnaryOperator#compose(LongUnaryOperator)}.
+     *
+     * @param before the operator to apply before this one.
+     * @return a composed {@code FailableLongUnaryOperator} like {@link LongUnaryOperator#compose(LongUnaryOperator)}.
+     * @throws NullPointerException if before is null.
+     * @see #andThen(FailableLongUnaryOperator)
+     */
+    default FailableLongUnaryOperator<E> compose(final FailableLongUnaryOperator<E> before) {
+        Objects.requireNonNull(before);
+        return (final long v) -> applyAsLong(before.applyAsLong(v));
+    }
+}

src/main/java/org/apache/commons/lang3/function/FailableObjDoubleConsumer.java

@@ -22,19 +22,34 @@
 /**
  * A functional interface like {@link ObjDoubleConsumer} that declares a {@code Throwable}.
  *
- * @param <O> the type of the object argument to the operation.
+ * @param <T> the type of the object argument to the operation.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableObjDoubleConsumer<O, T extends Throwable> {
+public interface FailableObjDoubleConsumer<T, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableObjDoubleConsumer NOP = (t, u) -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the object argument to the operation.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailableObjDoubleConsumer<T, E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
      * @param object the object parameter for the consumable to accept.
      * @param value the double parameter for the consumable to accept.
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(O object, double value) throws T;
+    void accept(T object, double value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableObjIntConsumer.java

@@ -22,19 +22,34 @@
 /**
  * A functional interface like {@link ObjIntConsumer} that declares a {@code Throwable}.
  *
- * @param <O> the type of the object argument to the operation.
+ * @param <T> the type of the object argument to the operation.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableObjIntConsumer<O, T extends Throwable> {
+public interface FailableObjIntConsumer<T, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableObjIntConsumer NOP = (t, u) -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the object argument to the operation.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailableObjIntConsumer<T, E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
      * @param object the object parameter for the consumable to accept.
      * @param value the int parameter for the consumable to accept.
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(O object, int value) throws T;
+    void accept(T object, int value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableObjLongConsumer.java

@@ -22,19 +22,34 @@
 /**
  * A functional interface like {@link ObjLongConsumer} that declares a {@code Throwable}.
  *
- * @param <O> the type of the object argument to the operation.
+ * @param <T> the type of the object argument to the operation.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableObjLongConsumer<O, T extends Throwable> {
+public interface FailableObjLongConsumer<T, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableObjLongConsumer NOP = (t, u) -> {/* NOP */};
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the object argument to the operation.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailableObjLongConsumer<T, E> nop() {
+        return NOP;
+    }
 
     /**
      * Accepts the consumer.
      *
      * @param object the object parameter for the consumable to accept.
      * @param value the long parameter for the consumable to accept.
-     * @throws T Thrown when the consumer fails.
+     * @throws E Thrown when the consumer fails.
      */
-    void accept(O object, long value) throws T;
+    void accept(T object, long value) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailablePredicate.java

@@ -17,24 +17,88 @@
 
 package org.apache.commons.lang3.function;
 
+import java.util.Objects;
 import java.util.function.Predicate;
 
 /**
  * A functional interface like {@link Predicate} that declares a {@code Throwable}.
  *
- * @param <I> Predicate type 1.
+ * @param <T> Predicate type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailablePredicate<I, T extends Throwable> {
+public interface FailablePredicate<T, E extends Throwable> {
+
+    /** FALSE singleton */
+    @SuppressWarnings("rawtypes")
+    FailablePredicate FALSE = t -> false;
+
+    /** TRUE singleton */
+    @SuppressWarnings("rawtypes")
+    FailablePredicate TRUE = t -> true;
+
+    /**
+     * Returns The FALSE singleton.
+     *
+     * @param <T> Predicate type.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailablePredicate<T, E> falsePredicate() {
+        return FALSE;
+    }
+
+    /**
+     * Returns The FALSE TRUE.
+     *
+     * @param <T> Predicate type.
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailablePredicate<T, E> truePredicate() {
+        return TRUE;
+    }
+
+    /**
+     * Returns a composed {@code FailablePredicate} like {@link Predicate#and(Predicate)}.
+     *
+     * @param other a predicate that will be logically-ANDed with this predicate.
+     * @return a composed {@code FailablePredicate} like {@link Predicate#and(Predicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailablePredicate<T, E> and(final FailablePredicate<? super T, E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) && other.test(t);
+    }
+
+    /**
+     * Returns a predicate that negates this predicate.
+     *
+     * @return a predicate that negates this predicate.
+     */
+    default FailablePredicate<T, E> negate() {
+        return t -> !test(t);
+    }
+
+    /**
+     * Returns a composed {@code FailablePredicate} like {@link Predicate#and(Predicate)}.
+     *
+     * @param other a predicate that will be logically-ORed with this predicate.
+     * @return a composed {@code FailablePredicate} like {@link Predicate#and(Predicate)}.
+     * @throws NullPointerException if other is null
+     */
+    default FailablePredicate<T, E> or(final FailablePredicate<? super T, E> other) {
+        Objects.requireNonNull(other);
+        return t -> test(t) || other.test(t);
+    }
 
     /**
      * Tests the predicate.
      *
      * @param object the object to test the predicate on
      * @return the predicate's evaluation
-     * @throws T if the predicate fails
+     * @throws E if the predicate fails
      */
-    boolean test(I object) throws T;
+    boolean test(T object) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableRunnable.java

@@ -20,16 +20,16 @@
 /**
  * A functional interface like {@link Runnable} that declares a {@code Throwable}.
  *
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableRunnable<T extends Throwable> {
+public interface FailableRunnable<E extends Throwable> {
 
     /**
      * Runs the function.
      *
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    void run() throws T;
+    void run() throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableSupplier.java

@@ -23,17 +23,17 @@
  * A functional interface like {@link Supplier} that declares a {@code Throwable}.
  *
  * @param <R> Return type.
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableSupplier<R, T extends Throwable> {
+public interface FailableSupplier<R, E extends Throwable> {
 
     /**
      * Supplies an object
      *
      * @return a result
-     * @throws T if the supplier fails
+     * @throws E if the supplier fails
      */
-    R get() throws T;
+    R get() throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableToDoubleBiFunction.java

@@ -22,13 +22,29 @@
 /**
  * A functional interface like {@link ToDoubleBiFunction} that declares a {@code Throwable}.
  *
- * @param <O1> the type of the first argument to the function
+ * @param <T> the type of the first argument to the function
- * @param <O2> the type of the second argument to the function
+ * @param <U> the type of the second argument to the function
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableToDoubleBiFunction<O1, O2, T extends Throwable> {
+public interface FailableToDoubleBiFunction<T, U, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableToDoubleBiFunction NOP = (t, u) -> 0d;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the first argument to the function
+     * @param <U> the type of the second argument to the function
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, U, E extends Throwable> FailableToDoubleBiFunction<T, U, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given arguments.
@@ -36,7 +52,7 @@ public interface FailableToDoubleBiFunction<O1, O2, T extends Throwable> {
      * @param t the first function argument
      * @param u the second function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    double applyAsDouble(O1 t, O2 u) throws T;
+    double applyAsDouble(T t, U u) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableToDoubleFunction.java

@@ -22,19 +22,34 @@
 /**
  * A functional interface like {@link ToDoubleFunction} that declares a {@code Throwable}.
  *
- * @param <I> the type of the first argument to the function
+ * @param <T> the type of the argument to the function
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableToDoubleFunction<I, T extends Throwable> {
+public interface FailableToDoubleFunction<T, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableToDoubleFunction NOP = t -> 0d;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the argument to the function
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailableToDoubleFunction<T, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given arguments.
      *
      * @param t the first function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    double applyAsDouble(I t) throws T;
+    double applyAsDouble(T t) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableToIntBiFunction.java

@@ -22,13 +22,29 @@
 /**
  * A functional interface like {@link ToIntBiFunction} that declares a {@code Throwable}.
  *
- * @param <O1> the type of the first argument to the function
+ * @param <T> the type of the first argument to the function
- * @param <O2> the type of the second argument to the function
+ * @param <U> the type of the second argument to the function
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableToIntBiFunction<O1, O2, T extends Throwable> {
+public interface FailableToIntBiFunction<T, U, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableToIntBiFunction NOP = (t, u) -> 0;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the first argument to the function
+     * @param <U> the type of the second argument to the function
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, U, E extends Throwable> FailableToIntBiFunction<T, U, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given arguments.
@@ -36,7 +52,7 @@ public interface FailableToIntBiFunction<O1, O2, T extends Throwable> {
      * @param t the first function argument
      * @param u the second function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    int applyAsInt(O1 t, O2 u) throws T;
+    int applyAsInt(T t, U u) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableToIntFunction.java

@@ -22,19 +22,34 @@
 /**
  * A functional interface like {@link ToIntFunction} that declares a {@code Throwable}.
  *
- * @param <I> the type of the first argument to the function
+ * @param <T> the type of the argument to the function
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableToIntFunction<I, T extends Throwable> {
+public interface FailableToIntFunction<T, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableToIntFunction NOP = t -> 0;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the argument to the function
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailableToIntFunction<T, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given arguments.
      *
      * @param t the first function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    int applyAsInt(I t) throws T;
+    int applyAsInt(T t) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableToLongBiFunction.java

@@ -22,13 +22,29 @@
 /**
  * A functional interface like {@link ToLongBiFunction} that declares a {@code Throwable}.
  *
- * @param <O1> the type of the first argument to the function
+ * @param <T> the type of the first argument to the function
- * @param <O2> the type of the second argument to the function
+ * @param <U> the type of the second argument to the function
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableToLongBiFunction<O1, O2, T extends Throwable> {
+public interface FailableToLongBiFunction<T, U, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableToLongBiFunction NOP = (t, u) -> 0;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the first argument to the function
+     * @param <U> the type of the second argument to the function
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, U, E extends Throwable> FailableToLongBiFunction<T, U, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given arguments.
@@ -36,7 +52,7 @@ public interface FailableToLongBiFunction<O1, O2, T extends Throwable> {
      * @param t the first function argument
      * @param u the second function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    long applyAsLong(O1 t, O2 u) throws T;
+    long applyAsLong(T t, U u) throws E;
 }

src/main/java/org/apache/commons/lang3/function/FailableToLongFunction.java

@@ -22,19 +22,34 @@
 /**
  * A functional interface like {@link ToLongFunction} that declares a {@code Throwable}.
  *
- * @param <I> the type of the first argument to the function
+ * @param <T> the type of the first argument to the function
- * @param <T> Thrown exception.
+ * @param <E> Thrown exception.
  * @since 3.11
  */
 @FunctionalInterface
-public interface FailableToLongFunction<I, T extends Throwable> {
+public interface FailableToLongFunction<T, E extends Throwable> {
+
+    /** NOP singleton */
+    @SuppressWarnings("rawtypes")
+    FailableToLongFunction NOP = t -> 0L;
+
+    /**
+     * Returns The NOP singleton.
+     *
+     * @param <T> the type of the argument to the function
+     * @param <E> Thrown exception.
+     * @return The NOP singleton.
+     */
+    static <T, E extends Throwable> FailableToLongFunction<T, E> nop() {
+        return NOP;
+    }
 
     /**
      * Applies this function to the given arguments.
      *
      * @param t the first function argument
      * @return the function result
-     * @throws T Thrown when the function fails.
+     * @throws E Thrown when the function fails.
      */
-    long applyAsLong(I t) throws T;
+    long applyAsLong(T t) throws E;
 }

src/main/java/org/apache/commons/lang3/function/package-info.java

@@ -15,13 +15,13 @@
  * limitations under the License.
  */
 /**
- * Provides functional interfaces to complement those in {@code java.lang.function} and utilities
+ * Provides functional interfaces to complement those in {@code java.lang.function} and utilities for working with Java
- * for working with Java 8 lambdas.
+ * 8 lambdas.
  *
- * <p>Contains failable functional interfaces that address the fact that lambdas are supposed not to
+ * <p>
- * throw Exceptions, at least not checked Exceptions, AKA instances of {@link java.lang.Exception}.
+ * Contains failable functional interfaces that address the fact that lambdas are supposed not to throw Exceptions, at
- * A failable functional interface declares a type of Exception that may be raised if the function
+ * least not checked Exceptions, A.K.A. instances of {@link java.lang.Exception}. A failable functional interface
- * fails.
+ * declares a type of Exception that may be raised if the function fails.
  *
  * @since 3.11
  */

src/main/java/org/apache/commons/lang3/math/NumberUtils.java

@@ -19,8 +19,8 @@
 import java.lang.reflect.Array;
 import java.math.BigDecimal;
 import java.math.BigInteger;
-
 import java.math.RoundingMode;
+
 import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.Validate;
 

src/main/java/org/apache/commons/lang3/text/StrLookup.java

@@ -29,8 +29,9 @@
  * If these do not suffice, you can subclass and implement your own matcher.
  * <p>
  * For example, it would be possible to implement a lookup that used the
- * key as a primary key, and looked up the value on demand from the database
+ * key as a primary key, and looked up the value on demand from the database.
  *
+ * @param <V> Unused.
  * @since 2.2
  * @deprecated as of 3.6, use commons-text
  * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/StringLookupFactory.html">

src/main/java/org/apache/commons/lang3/time/DateUtils.java

@@ -361,14 +361,14 @@ public static Date parseDateStrictly(final String str, final Locale locale, fina
      * @throws ParseException if none of the date patterns were suitable
      * @see java.util.Calendar#isLenient()
      */
-    private static Date parseDateWithLeniency(
+    private static Date parseDateWithLeniency(final String str, final Locale locale, final String[] parsePatterns,
-            final String str, final Locale locale, final String[] parsePatterns, final boolean lenient) throws ParseException {
+        final boolean lenient) throws ParseException {
         if (str == null || parsePatterns == null) {
             throw new IllegalArgumentException("Date and Patterns must not be null");
         }
 
         final TimeZone tz = TimeZone.getDefault();
-        final Locale lcl = locale==null ?Locale.getDefault() : locale;
+        final Locale lcl = locale == null ? Locale.getDefault() : locale;
         final ParsePosition pos = new ParsePosition(0);
         final Calendar calendar = Calendar.getInstance(tz, lcl);
         calendar.setLenient(lenient);
@@ -377,10 +377,10 @@ private static Date parseDateWithLeniency(
             final FastDateParser fdp = new FastDateParser(parsePattern, tz, lcl);
             calendar.clear();
             try {
-                if (fdp.parse(str, pos, calendar) && pos.getIndex()==str.length()) {
+                if (fdp.parse(str, pos, calendar) && pos.getIndex() == str.length()) {
                     return calendar.getTime();
                 }
-            } catch(final IllegalArgumentException ignore) {
+            } catch (final IllegalArgumentException ignore) {
                 // leniency is preventing calendar from being set
             }
             pos.setIndex(0);

src/main/java/org/apache/commons/lang3/tuple/ImmutablePair.java

@@ -69,6 +69,22 @@ public static <L, R> ImmutablePair<L, R>[] emptyArray() {
         return (ImmutablePair<L, R>[]) EMPTY_ARRAY;
     }
 
+    /**
+     * <p>Creates an immutable pair of two objects inferring the generic types.</p>
+     *
+     * <p>This factory allows the pair to be created using inference to
+     * obtain the generic types.</p>
+     *
+     * @param <L> the left element type
+     * @param <R> the right element type
+     * @param left  the left element, may be null
+     * @return a pair formed from the two parameters, not null
+     * @since 3.11
+     */
+    public static <L, R> Pair<L, R> left(final L left) {
+        return ImmutablePair.of(left, null);
+    }
+
     /**
      * Returns an immutable pair of nulls.
      *
@@ -122,6 +138,22 @@ public static <L, R> ImmutablePair<L, R> of(final Map.Entry<L, R> pair) {
         return new ImmutablePair<>(left, right);
     }
 
+    /**
+     * <p>Creates an immutable pair of two objects inferring the generic types.</p>
+     *
+     * <p>This factory allows the pair to be created using inference to
+     * obtain the generic types.</p>
+     *
+     * @param <L> the left element type
+     * @param <R> the right element type
+     * @param right  the right element, may be null
+     * @return a pair formed from the two parameters, not null
+     * @since 3.11
+     */
+    public static <L, R> Pair<L, R> right(final R right) {
+        return ImmutablePair.of(null, right);
+    }
+
     /** Left object */
     public final L left;
 

src/test/java/org/apache/commons/lang3/AnnotationUtilsTest.java

@@ -40,8 +40,8 @@
 import java.util.Collection;
 import java.util.Map;
 
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 
 /**
  */

src/test/java/org/apache/commons/lang3/ArchUtilsTest.java

@@ -16,17 +16,17 @@
  */
 package org.apache.commons.lang3;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import org.apache.commons.lang3.arch.Processor;
 import org.apache.commons.lang3.arch.Processor.Arch;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertNull;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
-
 /**
  * Test class for {@link ArchUtils}.
  */

src/test/java/org/apache/commons/lang3/ArrayUtilsTest.java

@@ -30,8 +30,8 @@
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Modifier;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.BitSet;
+import java.util.Collections;
 import java.util.Comparator;
 import java.util.Date;
 import java.util.Map;

src/test/java/org/apache/commons/lang3/CharEncodingTest.java

@@ -21,10 +21,10 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.jupiter.api.Test;
-
 import java.nio.charset.StandardCharsets;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Tests CharEncoding.
  *

src/test/java/org/apache/commons/lang3/ClassUtilsTest.java

@@ -16,13 +16,15 @@
  */
 package org.apache.commons.lang3;
 
-import org.apache.commons.lang3.ClassUtils.Interfaces;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
-import org.apache.commons.lang3.reflect.testbed.GenericConsumer;
+import static org.junit.jupiter.api.Assertions.assertEquals;
-import org.apache.commons.lang3.reflect.testbed.GenericParent;
+import static org.junit.jupiter.api.Assertions.assertFalse;
-import org.apache.commons.lang3.reflect.testbed.StringParameterizedChild;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
-import org.junit.jupiter.api.Assertions;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
-import org.junit.jupiter.api.DisplayName;
+import static org.junit.jupiter.api.Assertions.assertNull;
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
@@ -35,15 +37,13 @@
 import java.util.Map;
 import java.util.Set;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import org.apache.commons.lang3.ClassUtils.Interfaces;
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.apache.commons.lang3.reflect.testbed.GenericConsumer;
-import static org.junit.jupiter.api.Assertions.assertFalse;
+import org.apache.commons.lang3.reflect.testbed.GenericParent;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
+import org.apache.commons.lang3.reflect.testbed.StringParameterizedChild;
-import static org.junit.jupiter.api.Assertions.assertNotSame;
+import org.junit.jupiter.api.Assertions;
-import static org.junit.jupiter.api.Assertions.assertNull;
+import org.junit.jupiter.api.DisplayName;
-import static org.junit.jupiter.api.Assertions.assertSame;
+import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * Unit tests {@link org.apache.commons.lang3.ClassUtils}.

src/test/java/org/apache/commons/lang3/FunctionsTest.java

@@ -17,7 +17,6 @@
 package org.apache.commons.lang3;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
@@ -77,17 +76,17 @@ static boolean failingBool() throws SomeException {
             return true;
         }
 
-        static boolean testDouble(double value) throws SomeException {
+        static boolean testDouble(final double value) throws SomeException {
             throwOnOdd();
             return true;
         }
 
-        static boolean testInt(int value) throws SomeException {
+        static boolean testInt(final int value) throws SomeException {
             throwOnOdd();
             return true;
         }
 
-        static boolean testLong(long value) throws SomeException {
+        static boolean testLong(final long value) throws SomeException {
             throwOnOdd();
             return true;
         }
@@ -160,7 +159,7 @@ public void test() throws Throwable {
             test(throwable);
         }
 
-        public Object test(Object input1, Object input2) throws Throwable {
+        public Object test(final Object input1, final Object input2) throws Throwable {
             test(throwable);
             return acceptedObject;
         }
@@ -226,41 +225,41 @@ public long testAsLongPrimitive(final Throwable throwable) throws Throwable {
             return 0;
         }
 
-        public void testDouble(double i) throws Throwable {
+        public void testDouble(final double i) throws Throwable {
             test(throwable);
             acceptedPrimitiveObject1 = (P) ((Double) i);
         }
 
-        public double testDoubleDouble(double i, double j) throws Throwable {
+        public double testDoubleDouble(final double i, final double j) throws Throwable {
             test(throwable);
             acceptedPrimitiveObject1 = (P) ((Double) i);
             acceptedPrimitiveObject2 = (P) ((Double) j);
             return 3d;
         }
 
-        public void testInt(int i) throws Throwable {
+        public void testInt(final int i) throws Throwable {
             test(throwable);
             acceptedPrimitiveObject1 = (P) ((Integer) i);
         }
 
-        public void testLong(long i) throws Throwable {
+        public void testLong(final long i) throws Throwable {
             test(throwable);
             acceptedPrimitiveObject1 = (P) ((Long) i);
         }
 
-        public void testObjDouble(T object, double i) throws Throwable {
+        public void testObjDouble(final T object, final double i) throws Throwable {
             test(throwable);
             acceptedObject = object;
             acceptedPrimitiveObject1 = (P) ((Double) i);
         }
 
-        public void testObjInt(T object, int i) throws Throwable {
+        public void testObjInt(final T object, final int i) throws Throwable {
             test(throwable);
             acceptedObject = object;
             acceptedPrimitiveObject1 = (P) ((Integer) i);
         }
 
-        public void testObjLong(T object, long i) throws Throwable {
+        public void testObjLong(final T object, final long i) throws Throwable {
             test(throwable);
             acceptedObject = object;
             acceptedPrimitiveObject1 = (P) ((Long) i);
@@ -510,19 +509,6 @@ public void testApplyBiFunction() {
         assertEquals(0, i.intValue());
     }
 
-    @Test
-    public void testApplyDoubleBinaryOperator() {
-        final IllegalStateException ise = new IllegalStateException();
-        final Testable<?, Double> testable = new Testable<>(ise);
-        Throwable e = assertThrows(IllegalStateException.class,
-            () -> Functions.applyAsDouble(testable::testDoubleDouble, 1d, 2d));
-        assertSame(ise, e);
-
-        final Testable<?, Double> testable2 = new Testable<>(null);
-        final double i = Functions.applyAsDouble(testable2::testDoubleDouble, 1d, 2d);
-        assertEquals(3d, i);
-    }
-
     @Test
     public void testApplyFunction() {
         final IllegalStateException ise = new IllegalStateException();
@@ -736,103 +722,6 @@ public void testFunction() {
         assertEquals(0, function.apply(null).intValue());
     }
 
-    @Test
-    public void testGetAsBooleanSupplier() {
-        final IllegalStateException ise = new IllegalStateException();
-        final Testable<?, ?> testable = new Testable<>(ise);
-        Throwable e = assertThrows(IllegalStateException.class,
-            () -> Functions.getAsBoolean(testable::testAsBooleanPrimitive));
-        assertSame(ise, e);
-
-        final Error error = new OutOfMemoryError();
-        testable.setThrowable(error);
-        e = assertThrows(OutOfMemoryError.class, () -> Functions.getAsBoolean(testable::testAsBooleanPrimitive));
-        assertSame(error, e);
-
-        final IOException ioe = new IOException("Unknown I/O error");
-        testable.setThrowable(ioe);
-        e = assertThrows(UncheckedIOException.class, () -> Functions.getAsBoolean(testable::testAsBooleanPrimitive));
-        final Throwable t = e.getCause();
-        assertNotNull(t);
-        assertSame(ioe, t);
-
-        testable.setThrowable(null);
-        assertFalse(Functions.getAsBoolean(testable::testAsBooleanPrimitive));
-    }
-
-    @Test
-    public void testGetAsDoubleSupplier() {
-        final IllegalStateException ise = new IllegalStateException();
-        final Testable<?, ?> testable = new Testable<>(ise);
-        Throwable e = assertThrows(IllegalStateException.class,
-            () -> Functions.getAsDouble(testable::testAsDoublePrimitive));
-        assertSame(ise, e);
-
-        final Error error = new OutOfMemoryError();
-        testable.setThrowable(error);
-        e = assertThrows(OutOfMemoryError.class, () -> Functions.getAsDouble(testable::testAsDoublePrimitive));
-        assertSame(error, e);
-
-        final IOException ioe = new IOException("Unknown I/O error");
-        testable.setThrowable(ioe);
-        e = assertThrows(UncheckedIOException.class, () -> Functions.getAsDouble(testable::testAsDoublePrimitive));
-        final Throwable t = e.getCause();
-        assertNotNull(t);
-        assertSame(ioe, t);
-
-        testable.setThrowable(null);
-        assertEquals(0, Functions.getAsDouble(testable::testAsDoublePrimitive));
-    }
-
-    @Test
-    public void testGetAsIntSupplier() {
-        final IllegalStateException ise = new IllegalStateException();
-        final Testable<?, ?> testable = new Testable<>(ise);
-        Throwable e = assertThrows(IllegalStateException.class, () -> Functions.getAsInt(testable::testAsIntPrimitive));
-        assertSame(ise, e);
-
-        final Error error = new OutOfMemoryError();
-        testable.setThrowable(error);
-        e = assertThrows(OutOfMemoryError.class, () -> Functions.getAsInt(testable::testAsIntPrimitive));
-        assertSame(error, e);
-
-        final IOException ioe = new IOException("Unknown I/O error");
-        testable.setThrowable(ioe);
-        e = assertThrows(UncheckedIOException.class, () -> Functions.getAsInt(testable::testAsIntPrimitive));
-        final Throwable t = e.getCause();
-        assertNotNull(t);
-        assertSame(ioe, t);
-
-        testable.setThrowable(null);
-        final int i = Functions.getAsInt(testable::testAsInteger);
-        assertEquals(0, i);
-    }
-
-    @Test
-    public void testGetAsLongSupplier() {
-        final IllegalStateException ise = new IllegalStateException();
-        final Testable<?, ?> testable = new Testable<>(ise);
-        Throwable e = assertThrows(IllegalStateException.class,
-            () -> Functions.getAsLong(testable::testAsLongPrimitive));
-        assertSame(ise, e);
-
-        final Error error = new OutOfMemoryError();
-        testable.setThrowable(error);
-        e = assertThrows(OutOfMemoryError.class, () -> Functions.getAsLong(testable::testAsLongPrimitive));
-        assertSame(error, e);
-
-        final IOException ioe = new IOException("Unknown I/O error");
-        testable.setThrowable(ioe);
-        e = assertThrows(UncheckedIOException.class, () -> Functions.getAsLong(testable::testAsLongPrimitive));
-        final Throwable t = e.getCause();
-        assertNotNull(t);
-        assertSame(ioe, t);
-
-        testable.setThrowable(null);
-        final long i = Functions.getAsLong(testable::testAsLongPrimitive);
-        assertEquals(0, i);
-    }
-
     @Test
     public void testGetFromSupplier() {
         FailureOnOddInvocations.invocations = 0;
@@ -911,7 +800,7 @@ public void testThrows_FailableBiConsumer_Object_Throwable() {
         new Functions.FailableBiConsumer<Object, Object, Throwable>() {
 
             @Override
-            public void accept(Object object1, Object object2) throws Throwable {
+            public void accept(final Object object1, final Object object2) throws Throwable {
                 throw new IOException("test");
             }
         };
@@ -926,7 +815,7 @@ public void testThrows_FailableBiConsumer_String_IOException() {
         new Functions.FailableBiConsumer<String, String, IOException>() {
 
             @Override
-            public void accept(String object1, String object2) throws IOException {
+            public void accept(final String object1, final String object2) throws IOException {
                 throw new IOException("test");
 
             }
@@ -942,7 +831,7 @@ public void testThrows_FailableBiFunction_Object_Throwable() {
         new Functions.FailableBiFunction<Object, Object, Object, Throwable>() {
 
             @Override
-            public Object apply(Object input1, Object input2) throws Throwable {
+            public Object apply(final Object input1, final Object input2) throws Throwable {
                 throw new IOException("test");
             }
         };
@@ -957,7 +846,7 @@ public void testThrows_FailableBiFunction_String_IOException() {
         new Functions.FailableBiFunction<String, String, String, IOException>() {
 
             @Override
-            public String apply(String input1, String input2) throws IOException {
+            public String apply(final String input1, final String input2) throws IOException {
                 throw new IOException("test");
             }
         };
@@ -972,7 +861,7 @@ public void testThrows_FailableBiPredicate_Object_Throwable() {
         new Functions.FailableBiPredicate<Object, Object, Throwable>() {
 
             @Override
-            public boolean test(Object object1, Object object2) throws Throwable {
+            public boolean test(final Object object1, final Object object2) throws Throwable {
                 throw new IOException("test");
             }
         };
@@ -987,7 +876,7 @@ public void testThrows_FailableBiPredicate_String_IOException() {
         new Functions.FailableBiPredicate<String, String, IOException>() {
 
             @Override
-            public boolean test(String object1, String object2) throws IOException {
+            public boolean test(final String object1, final String object2) throws IOException {
                 throw new IOException("test");
             }
         };
@@ -1032,7 +921,7 @@ public void testThrows_FailableConsumer_Object_Throwable() {
         new Functions.FailableConsumer<Object, Throwable>() {
 
             @Override
-            public void accept(Object object) throws Throwable {
+            public void accept(final Object object) throws Throwable {
                 throw new IOException("test");
 
             }
@@ -1048,7 +937,7 @@ public void testThrows_FailableConsumer_String_IOException() {
         new Functions.FailableConsumer<String, IOException>() {
 
             @Override
-            public void accept(String object) throws IOException {
+            public void accept(final String object) throws IOException {
                 throw new IOException("test");
 
             }
@@ -1064,7 +953,7 @@ public void testThrows_FailableFunction_Object_Throwable() {
         new Functions.FailableFunction<Object, Object, Throwable>() {
 
             @Override
-            public Object apply(Object input) throws Throwable {
+            public Object apply(final Object input) throws Throwable {
                 throw new IOException("test");
             }
         };
@@ -1079,7 +968,7 @@ public void testThrows_FailableFunction_String_IOException() {
         new Functions.FailableFunction<String, String, IOException>() {
 
             @Override
-            public String apply(String input) throws IOException {
+            public String apply(final String input) throws IOException {
                 throw new IOException("test");
             }
         };
@@ -1094,7 +983,7 @@ public void testThrows_FailablePredicate_Object_Throwable() {
         new Functions.FailablePredicate<Object, Throwable>() {
 
             @Override
-            public boolean test(Object object) throws Throwable {
+            public boolean test(final Object object) throws Throwable {
                 throw new IOException("test");
             }
         };
@@ -1109,7 +998,7 @@ public void testThrows_FailablePredicate_String_IOException() {
         new Functions.FailablePredicate<String, IOException>() {
 
             @Override
-            public boolean test(String object) throws IOException {
+            public boolean test(final String object) throws IOException {
                 throw new IOException("test");
             }
         };

src/test/java/org/apache/commons/lang3/JavaVersionTest.java

@@ -18,8 +18,6 @@
  */
 package org.apache.commons.lang3;
 
-import org.junit.jupiter.api.Test;
-
 import static org.apache.commons.lang3.JavaVersion.JAVA_0_9;
 import static org.apache.commons.lang3.JavaVersion.JAVA_10;
 import static org.apache.commons.lang3.JavaVersion.JAVA_11;
@@ -27,6 +25,7 @@
 import static org.apache.commons.lang3.JavaVersion.JAVA_13;
 import static org.apache.commons.lang3.JavaVersion.JAVA_14;
 import static org.apache.commons.lang3.JavaVersion.JAVA_15;
+import static org.apache.commons.lang3.JavaVersion.JAVA_16;
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_1;
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_2;
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_3;
@@ -43,6 +42,8 @@
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Unit tests {@link org.apache.commons.lang3.JavaVersion}.
  */
@@ -66,10 +67,11 @@ public void testGetJavaVersion() {
         assertEquals(JAVA_13, get("13"), "13 failed");
         assertEquals(JAVA_14, get("14"), "14 failed");
         assertEquals(JAVA_15, get("15"), "15 failed");
+        assertEquals(JAVA_16, get("16"), "16 failed");
         assertEquals(JAVA_RECENT, get("1.10"), "1.10 failed");
         // assertNull("2.10 unexpectedly worked", get("2.10"));
         assertEquals(get("1.5"), getJavaVersion("1.5"), "Wrapper method failed");
-        assertEquals(JAVA_RECENT, get("16"), "Unhandled"); // LANG-1384
+        assertEquals(JAVA_RECENT, get("17"), "Unhandled"); // LANG-1384
     }
 
     @Test

src/test/java/org/apache/commons/lang3/NotImplementedExceptionTest.java

@@ -16,10 +16,11 @@
  */
 package org.apache.commons.lang3;
 
-import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Unit tests {@link org.apache.commons.lang3.NotImplementedException}.
  */

src/test/java/org/apache/commons/lang3/ObjectUtilsTest.java

@@ -361,6 +361,15 @@ public void testToString_ObjectString() {
         assertEquals(Boolean.TRUE.toString(), ObjectUtils.toString(Boolean.TRUE, BAR) );
     }
 
+    @Test
+    public void testToString_SupplierString() {
+        assertEquals(null, ObjectUtils.toString(null, (Supplier<String>) null));
+        assertEquals(null, ObjectUtils.toString(null, () -> null));
+        // Pretend computing BAR is expensive.
+        assertEquals(BAR, ObjectUtils.toString(null, () -> BAR));
+        assertEquals(Boolean.TRUE.toString(), ObjectUtils.toString(Boolean.TRUE, () -> BAR));
+    }
+
     @SuppressWarnings("cast") // 1 OK, because we are checking for code change
     @Test
     public void testNull() {

src/test/java/org/apache/commons/lang3/RandomUtilsTest.java

@@ -23,11 +23,11 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.jupiter.api.Test;
-
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Modifier;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Tests for {@link RandomUtils}
  */

src/test/java/org/apache/commons/lang3/StringUtilsContainsTest.java

@@ -232,17 +232,10 @@ public void testContainsAny_StringStringArray() {
     public void testContainsIgnoreCase_LocaleIndependence() {
         final Locale[] locales = { Locale.ENGLISH, new Locale("tr"), Locale.getDefault() };
 
-        final String[][] tdata = {
+        final String[][] tdata = { { "i", "I" }, { "I", "i" }, { "\u03C2", "\u03C3" }, { "\u03A3", "\u03C2" },
-            { "i", "I" },
+            { "\u03A3", "\u03C3" }, };
-            { "I", "i" },
-            { "\u03C2", "\u03C3" },
-            { "\u03A3", "\u03C2" },
-            { "\u03A3", "\u03C3" },
-        };
 
-        final String[][] fdata = {
+        final String[][] fdata = { { "\u00DF", "SS" }, };
-            { "\u00DF", "SS" },
-        };
 
         for (final Locale testLocale : locales) {
             Locale.setDefault(testLocale);

src/test/java/org/apache/commons/lang3/StringUtilsStartsEndsWithTest.java

@@ -16,11 +16,11 @@
  */
 package org.apache.commons.lang3;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
+
 
 /**
  * Unit tests {@link org.apache.commons.lang3.StringUtils} - StartsWith/EndsWith methods

src/test/java/org/apache/commons/lang3/StringUtilsTest.java

@@ -60,11 +60,11 @@ public class StringUtilsTest {
     static final String NON_TRIMMABLE;
 
     static {
-        StringBuilder ws = new StringBuilder();
+        final StringBuilder ws = new StringBuilder();
-        StringBuilder nws = new StringBuilder();
+        final StringBuilder nws = new StringBuilder();
         final String hs = String.valueOf(((char) 160));
-        StringBuilder tr = new StringBuilder();
+        final StringBuilder tr = new StringBuilder();
-        StringBuilder ntr = new StringBuilder();
+        final StringBuilder ntr = new StringBuilder();
         for (int i = 0; i < Character.MAX_VALUE; i++) {
             if (Character.isWhitespace((char) i)) {
                 ws.append(String.valueOf((char) i));
@@ -3279,12 +3279,12 @@ public void testToRootLowerCase() {
         assertEquals("title", "TITLE".toLowerCase(Locale.ROOT));
         assertEquals("title", StringUtils.toRootLowerCase("TITLE"));
         // Make sure we are not using the default Locale:
-        final Locale defaultLocales = Locale.getDefault();
+        final Locale defaultLocale = Locale.getDefault();
         try {
             Locale.setDefault(TURKISH);
             assertEquals("title", StringUtils.toRootLowerCase("TITLE"));
         } finally {
-            Locale.setDefault(defaultLocales);
+            Locale.setDefault(defaultLocale);
         }
     }
 
@@ -3299,36 +3299,36 @@ public void testToRootUpperCase() {
         assertEquals("TITLE", "title".toUpperCase(Locale.ROOT));
         assertEquals("TITLE", StringUtils.toRootUpperCase("title"));
         // Make sure we are not using the default Locale:
-        final Locale defaultLocales = Locale.getDefault();
+        final Locale defaultLocale = Locale.getDefault();
         try {
             Locale.setDefault(TURKISH);
             assertEquals("TITLE", StringUtils.toRootUpperCase("title"));
         } finally {
-            Locale.setDefault(defaultLocales);
+            Locale.setDefault(defaultLocale);
         }
     }
 
     @Test
     public void testGeorgianSample() {
-        char[] arrayI = new char[]{
+        final char[] arrayI = new char[]{
                 //Latin Small Letter dotless I
                 (char) 0x0131,
                 //Greek Capital Letter Theta
                 (char) 0x03F4
         };
-        char[] arrayJ = new char[]{
+        final char[] arrayJ = new char[]{
                 //Latin Capital Letter I with dot above
                 (char) 0x0130,
                 //Greek Theta Symbol
                 (char) 0x03D1
         };
-        for (char i : arrayI) {
+        for (final char i : arrayI) {
-            for (char j : arrayJ) {
+            for (final char j : arrayJ) {
-                String si = String.valueOf(i);
+                final String si = String.valueOf(i);
-                String sj = String.valueOf(j);
+                final String sj = String.valueOf(j);
-                boolean res1 = si.equalsIgnoreCase(sj);
+                final boolean res1 = si.equalsIgnoreCase(sj);
-                CharSequence ci = new StringBuilder(si);
+                final CharSequence ci = new StringBuilder(si);
-                CharSequence cj = new StringBuilder(sj);
+                final CharSequence cj = new StringBuilder(sj);
                 boolean res2 = StringUtils.startsWithIgnoreCase(ci, cj);
                 assertEquals(res1, res2, "si : " + si + " sj : " + sj);
                 res2 = StringUtils.endsWithIgnoreCase(ci, cj);

src/test/java/org/apache/commons/lang3/SystemUtilsTest.java

@@ -19,6 +19,10 @@
 
 package org.apache.commons.lang3;
 
+import static org.apache.commons.lang3.JavaVersion.JAVA_10;
+import static org.apache.commons.lang3.JavaVersion.JAVA_11;
+import static org.apache.commons.lang3.JavaVersion.JAVA_12;
+import static org.apache.commons.lang3.JavaVersion.JAVA_13;
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_1;
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_2;
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_3;
@@ -28,10 +32,6 @@
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_7;
 import static org.apache.commons.lang3.JavaVersion.JAVA_1_8;
 import static org.apache.commons.lang3.JavaVersion.JAVA_9;
-import static org.apache.commons.lang3.JavaVersion.JAVA_10;
-import static org.apache.commons.lang3.JavaVersion.JAVA_11;
-import static org.apache.commons.lang3.JavaVersion.JAVA_12;
-import static org.apache.commons.lang3.JavaVersion.JAVA_13;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;

src/test/java/org/apache/commons/lang3/ThreadUtilsTest.java

@@ -323,7 +323,7 @@ public void testComplexThreadGroups() throws Exception {
             assertEquals(1, ThreadUtils.findThreadsByName(t4.getName(), threadGroup3.getName()).size());
             assertEquals(0, ThreadUtils.findThreadsByName(t4.getName(), threadGroup2.getName()).size());
             assertEquals(2, ThreadUtils.findThreadsByName(t11.getName(), threadGroup7.getName()).size());
-        }finally {
+        } finally {
             for (final Thread thread : threads) {
                 thread.interrupt();
                 thread.join();

src/test/java/org/apache/commons/lang3/ValidateTest.java

@@ -18,8 +18,12 @@
  */
 package org.apache.commons.lang3;
 
-import org.junit.jupiter.api.Nested;
+import static org.junit.jupiter.api.Assertions.assertEquals;
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Modifier;
@@ -29,12 +33,8 @@
 import java.util.Map;
 import java.util.Set;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Nested;
-import static org.junit.jupiter.api.Assertions.assertFalse;
+import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertSame;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * Unit tests {@link org.apache.commons.lang3.Validate}.

src/test/java/org/apache/commons/lang3/builder/JsonToStringStyleTest.java

@@ -20,8 +20,11 @@
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.List;
 
 import org.apache.commons.lang3.builder.ToStringStyleTest.Person;
 import org.junit.jupiter.api.AfterEach;
@@ -181,6 +184,73 @@ public void testObject() {
                         .toString());
     }
 
+    @Test
+    public void testList() {
+        final Student student = new Student();
+        final ArrayList<Hobby> objects = new ArrayList<>();
+
+        objects.add(Hobby.BOOK);
+        objects.add(Hobby.SPORT);
+        objects.add(Hobby.MUSIC);
+
+        student.setHobbies(objects);
+
+        assertEquals(student.toString(), "{\"hobbies\":[\"BOOK\",\"SPORT\",\"MUSIC\"]}");
+        student.setHobbies(new ArrayList<>());
+        assertEquals(student.toString(), "{\"hobbies\":[]}");
+        student.setHobbies(null);
+        assertEquals(student.toString(), "{\"hobbies\":null}");
+    }
+
+    @Test
+    public void testArrayEnum() {
+        final Teacher teacher = new Teacher();
+        final Hobby[] hobbies = new Hobby[3];
+        hobbies[0] = Hobby.BOOK;
+        hobbies[1] = Hobby.SPORT;
+        hobbies[2] = Hobby.MUSIC;
+
+        teacher.setHobbies(hobbies);
+
+        assertEquals(teacher.toString(), "{\"hobbies\":[\"BOOK\",\"SPORT\",\"MUSIC\"]}");
+        teacher.setHobbies(new Hobby[0]);
+        assertEquals(teacher.toString(), "{\"hobbies\":[]}");
+        teacher.setHobbies(null);
+        assertEquals(teacher.toString(), "{\"hobbies\":null}");
+    }
+
+    @Test
+    public void testCombineListAndEnum() {
+        final Teacher teacher = new Teacher();
+
+        final Hobby[] teacherHobbies = new Hobby[3];
+        teacherHobbies[0] = Hobby.BOOK;
+        teacherHobbies[1] = Hobby.SPORT;
+        teacherHobbies[2] = Hobby.MUSIC;
+
+        teacher.setHobbies(teacherHobbies);
+
+        final Student john = new Student();
+        john.setHobbies(Arrays.asList(Hobby.BOOK, Hobby.MUSIC));
+
+        final Student alice = new Student();
+        alice.setHobbies(new ArrayList<>());
+
+        final Student bob = new Student();
+        bob.setHobbies(Collections.singletonList(Hobby.BOOK));
+
+        final ArrayList<Student> students = new ArrayList<>();
+        students.add(john);
+        students.add(alice);
+        students.add(bob);
+
+        final AcademyClass academyClass = new AcademyClass();
+        academyClass.setStudents(students);
+        academyClass.setTeacher(teacher);
+
+        assertEquals(academyClass.toString(), "{\"students\":[{\"hobbies\":[\"BOOK\",\"MUSIC\"]},{\"hobbies\":[]},{\"hobbies\":[\"BOOK\"]}],\"teacher\":{\"hobbies\":[\"BOOK\",\"SPORT\",\"MUSIC\"]}}");
+    }
+
     @Test
     public void testPerson() {
         final Person p = new Person();
@@ -477,4 +547,73 @@ static class NestingPerson {
          */
         Person person;
     }
+
+    enum Hobby {
+        SPORT,
+        BOOK,
+        MUSIC
+    }
+
+    enum EmptyEnum {
+    }
+
+    static class Student {
+        List<Hobby> hobbies;
+
+        public List<Hobby> getHobbies() {
+            return hobbies;
+        }
+
+        public void setHobbies(final List<Hobby> hobbies) {
+            this.hobbies = hobbies;
+        }
+
+        @Override
+        public String toString() {
+            return ToStringBuilder.reflectionToString(this);
+        }
+    }
+
+    static class Teacher {
+        Hobby[] hobbies;
+
+        public Hobby[] getHobbies() {
+            return hobbies;
+        }
+
+        public void setHobbies(final Hobby[] hobbies) {
+            this.hobbies = hobbies;
+        }
+
+        @Override
+        public String toString() {
+            return ToStringBuilder.reflectionToString(this);
+        }
+    }
+
+    static class AcademyClass {
+        Teacher teacher;
+        List<Student> students;
+
+        public void setTeacher(final Teacher teacher) {
+            this.teacher = teacher;
+        }
+
+        public void setStudents(final List<Student> students) {
+            this.students = students;
+        }
+
+        public Teacher getTeacher() {
+            return teacher;
+        }
+
+        public List<Student> getStudents() {
+            return students;
+        }
+
+        @Override
+        public String toString() {
+            return ToStringBuilder.reflectionToString(this);
+        }
+    }
 }

src/test/java/org/apache/commons/lang3/builder/NoClassNameToStringStyleTest.java

@@ -16,15 +16,15 @@
  */
 package org.apache.commons.lang3.builder;
 
-import org.apache.commons.lang3.builder.ToStringStyleTest.Person;
+import static org.junit.jupiter.api.Assertions.assertEquals;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
 
 import java.util.ArrayList;
 import java.util.HashMap;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.apache.commons.lang3.builder.ToStringStyleTest.Person;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 
 /**
  * Unit tests {@link ToStringStyle#NO_CLASS_NAME_STYLE}.

src/test/java/org/apache/commons/lang3/builder/ReflectionToStringBuilderExcludeWithAnnotationTest.java

@@ -17,9 +17,9 @@
 
 package org.apache.commons.lang3.builder;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.not;
-import static org.hamcrest.MatcherAssert.assertThat;
 
 import org.junit.jupiter.api.Test;
 

src/test/java/org/apache/commons/lang3/builder/ReflectionToStringBuilderSummaryTest.java

@@ -16,10 +16,10 @@
  */
 package org.apache.commons.lang3.builder;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import org.junit.jupiter.api.Test;
+
 public class ReflectionToStringBuilderSummaryTest {
 
     @SuppressWarnings("unused")

src/test/java/org/apache/commons/lang3/builder/ReflectionToStringBuilderTest.java

@@ -16,10 +16,10 @@
  */
 package org.apache.commons.lang3.builder;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.Test;
+
 public class ReflectionToStringBuilderTest {
 
     @Test

src/test/java/org/apache/commons/lang3/concurrent/BackgroundInitializerTest.java

@@ -16,8 +16,6 @@
  */
 package org.apache.commons.lang3.concurrent;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -32,6 +30,8 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 
+import org.junit.jupiter.api.Test;
+
 public class BackgroundInitializerTest {
     /**
      * Helper method for checking whether the initialize() method was correctly

src/test/java/org/apache/commons/lang3/concurrent/CircuitBreakingExceptionTest.java

@@ -16,14 +16,14 @@
  */
 package org.apache.commons.lang3.concurrent;
 
-import org.apache.commons.lang3.exception.AbstractExceptionTest;
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.apache.commons.lang3.exception.AbstractExceptionTest;
+import org.junit.jupiter.api.Test;
+
 
 /**
  * JUnit tests for {@link CircuitBreakingException}.

src/test/java/org/apache/commons/lang3/concurrent/ConcurrentUtilsTest.java

@@ -18,8 +18,8 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;

src/test/java/org/apache/commons/lang3/concurrent/LocksTest.java

@@ -44,7 +44,7 @@ public void testWriteLock() throws Exception {
         runTest(DELAY, true, l -> assertTrue(l >= NUMBER_OF_THREADS*DELAY));
     }
 
-    private void runTest(long delay, boolean exclusiveLock, LongConsumer runTimeCheck) throws InterruptedException {
+    private void runTest(final long delay, final boolean exclusiveLock, final LongConsumer runTimeCheck) throws InterruptedException {
         final boolean[] booleanValues = new boolean[10];
         final Lock<boolean[]> lock = Locks.lock(booleanValues);
         final boolean[] runningValues = new boolean[10];
@@ -60,9 +60,9 @@ private void runTest(long delay, boolean exclusiveLock, LongConsumer runTimeChec
             };
             final Thread t = new Thread(() -> {
                 if (exclusiveLock) {
-                    lock.runWriteLocked(consumer);
+                    lock.acceptWriteLocked(consumer);
                 } else {
-                    lock.runReadLocked(consumer);
+                    lock.acceptReadLocked(consumer);
                 }
             });
             modify(runningValues, i, true);
@@ -78,13 +78,13 @@ private void runTest(long delay, boolean exclusiveLock, LongConsumer runTimeChec
         runTimeCheck.accept(endTime-startTime);
     }
 
-    protected void modify(boolean[] booleanArray, int offset, boolean value) {
+    protected void modify(final boolean[] booleanArray, final int offset, final boolean value) {
         synchronized(booleanArray) {
             booleanArray[offset] = value;
         }
     }
 
-    protected boolean someValueIsTrue(boolean[] booleanArray) {
+    protected boolean someValueIsTrue(final boolean[] booleanArray) {
         synchronized(booleanArray) {
             for (int i = 0;  i < booleanArray.length;  i++) {
                 if (booleanArray[i]) {

src/test/java/org/apache/commons/lang3/concurrent/MemoizerTest.java

@@ -16,15 +16,15 @@
  */
 package org.apache.commons.lang3.concurrent;
 
-import org.easymock.EasyMock;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
 import static org.easymock.EasyMock.expect;
 import static org.easymock.EasyMock.replay;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.easymock.EasyMock;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
 public class MemoizerTest {
 
     private Computable<Integer, Integer> computable;

src/test/java/org/apache/commons/lang3/exception/AbstractExceptionContextTest.java

@@ -16,9 +16,6 @@
  */
 package org.apache.commons.lang3.exception;
 
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.BeforeEach;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -33,6 +30,8 @@
 
 import org.apache.commons.lang3.SerializationUtils;
 import org.apache.commons.lang3.tuple.Pair;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 
 
 /**

src/test/java/org/apache/commons/lang3/exception/CloneFailedExceptionTest.java

@@ -16,13 +16,13 @@
  */
 package org.apache.commons.lang3.exception;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests for {@link CloneFailedExceptionTest}.
  */

src/test/java/org/apache/commons/lang3/math/NumberUtilsTest.java

@@ -27,8 +27,8 @@
 import java.lang.reflect.Modifier;
 import java.math.BigDecimal;
 import java.math.BigInteger;
-
 import java.math.RoundingMode;
+
 import org.junit.jupiter.api.Test;
 
 /**

src/test/java/org/apache/commons/lang3/mutable/MutableBooleanTest.java

@@ -17,14 +17,14 @@
 
 package org.apache.commons.lang3.mutable;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests.
  *

src/test/java/org/apache/commons/lang3/mutable/MutableByteTest.java

@@ -16,12 +16,12 @@
  */
 package org.apache.commons.lang3.mutable;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests.
  *

src/test/java/org/apache/commons/lang3/mutable/MutableDoubleTest.java

@@ -16,13 +16,13 @@
  */
 package org.apache.commons.lang3.mutable;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests.
  *

src/test/java/org/apache/commons/lang3/mutable/MutableFloatTest.java

@@ -16,13 +16,13 @@
  */
 package org.apache.commons.lang3.mutable;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests.
  *

src/test/java/org/apache/commons/lang3/mutable/MutableIntTest.java

@@ -16,12 +16,12 @@
  */
 package org.apache.commons.lang3.mutable;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests.
  *

src/test/java/org/apache/commons/lang3/mutable/MutableLongTest.java

@@ -16,12 +16,12 @@
  */
 package org.apache.commons.lang3.mutable;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests.
  *

src/test/java/org/apache/commons/lang3/mutable/MutableShortTest.java

@@ -16,12 +16,12 @@
  */
 package org.apache.commons.lang3.mutable;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * JUnit tests.
  *