diff --git a/src/main/java/org/apache/commons/collections4/multiset/AbstractMultiSet.java b/src/main/java/org/apache/commons/collections4/multiset/AbstractMultiSet.java
index 0dbac0843..c3d13eb46 100644
--- a/src/main/java/org/apache/commons/collections4/multiset/AbstractMultiSet.java
+++ b/src/main/java/org/apache/commons/collections4/multiset/AbstractMultiSet.java
@@ -256,7 +256,7 @@ public abstract class AbstractMultiSet<E> extends AbstractCollection<E> implemen
      * @return the uniqueSet iterator
      */
     protected Iterator<E> createUniqueSetIterator() {
-        final Transformer<Entry<E>, E> transformer = entry -> entry.getElement();
+        final Transformer<Entry<E>, E> transformer = Entry::getElement;
         return IteratorUtils.transformedIterator(entrySet().iterator(), transformer);
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/MapUtilsTest.java b/src/test/java/org/apache/commons/collections4/MapUtilsTest.java
index bf8443a99..c131fa53d 100644
--- a/src/test/java/org/apache/commons/collections4/MapUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/MapUtilsTest.java
@@ -939,7 +939,7 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals(2.0, MapUtils.getDoubleValue(in, "key", 0.0), 0);
         assertEquals(2.0, MapUtils.getDoubleValue(in, "key"), 0);
         assertEquals(1.0, MapUtils.getDoubleValue(in, "noKey", 1.0), 0);
-        assertEquals(5.0, MapUtils.getDoubleValue(in, "noKey", (key)->{
+        assertEquals(5.0, MapUtils.getDoubleValue(in, "noKey", key -> {
             //sometimes the default value need to be calculated,such as System.currentTimeMillis()
             return 5.0D;
         }), 0);
@@ -947,7 +947,7 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals(0, MapUtils.getDoubleValue(in, "noKey"), 0);
         assertEquals(2.0, MapUtils.getDouble(in, "key", 0.0), 0);
         assertEquals(1.0, MapUtils.getDouble(in, "noKey", 1.0), 0);
-        assertEquals(1.0, MapUtils.getDouble(in, "noKey", (key)->{
+        assertEquals(1.0, MapUtils.getDouble(in, "noKey", key -> {
             return 1.0;
         }), 0);
 
@@ -967,13 +967,13 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals(2.0, MapUtils.getFloatValue(in, "key", 0.0f), 0);
         assertEquals(2.0, MapUtils.getFloatValue(in, "key"), 0);
         assertEquals(1.0, MapUtils.getFloatValue(in, "noKey", 1.0f), 0);
-        assertEquals(1.0, MapUtils.getFloatValue(in, "noKey", (key) -> {
+        assertEquals(1.0, MapUtils.getFloatValue(in, "noKey", key -> {
             return 1.0F;
         }), 0);
         assertEquals(0, MapUtils.getFloatValue(in, "noKey"), 0);
         assertEquals(2.0, MapUtils.getFloat(in, "key", 0.0f), 0);
         assertEquals(1.0, MapUtils.getFloat(in, "noKey", 1.0f), 0);
-        assertEquals(1.0, MapUtils.getFloat(in, "noKey", (key) -> {
+        assertEquals(1.0, MapUtils.getFloat(in, "noKey", key -> {
             return 1.0F;
         }), 0);
 
@@ -992,13 +992,13 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals(2.0, MapUtils.getLongValue(in, "key", 0L), 0);
         assertEquals(2.0, MapUtils.getLongValue(in, "key"), 0);
         assertEquals(1, MapUtils.getLongValue(in, "noKey", 1L), 0);
-        assertEquals(1, MapUtils.getLongValue(in, "noKey", (key) -> {
+        assertEquals(1, MapUtils.getLongValue(in, "noKey", key -> {
             return 1L;
         }), 0);
         assertEquals(0, MapUtils.getLongValue(in, "noKey"), 0);
         assertEquals(2.0, MapUtils.getLong(in, "key", 0L), 0);
         assertEquals(1, MapUtils.getLong(in, "noKey", 1L), 0);
-        assertEquals(1, MapUtils.getLong(in, "noKey", (key) -> {
+        assertEquals(1, MapUtils.getLong(in, "noKey", key -> {
             return 1L;
         }), 0);
 
@@ -1018,13 +1018,13 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals(2, MapUtils.getIntValue(in, "key", 0), 0);
         assertEquals(2, MapUtils.getIntValue(in, "key"), 0);
         assertEquals(0, MapUtils.getIntValue(in, "noKey", 0), 0);
-        assertEquals(0, MapUtils.getIntValue(in, "noKey", (key)->{
+        assertEquals(0, MapUtils.getIntValue(in, "noKey", key -> {
             return 0;
         }), 0);
         assertEquals(0, MapUtils.getIntValue(in, "noKey"), 0);
         assertEquals(2, MapUtils.getInteger(in, "key", 0), 0);
         assertEquals(0, MapUtils.getInteger(in, "noKey", 0), 0);
-        assertEquals(0, MapUtils.getInteger(in, "noKey", (key)->{
+        assertEquals(0, MapUtils.getInteger(in, "noKey", key -> {
             return 0;
         }), 0);
 
@@ -1043,13 +1043,13 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals(val, MapUtils.getShortValue(in, "key", val), 0);
         assertEquals(val, MapUtils.getShortValue(in, "key"), 0);
         assertEquals(val, MapUtils.getShortValue(in, "noKey", val), 0);
-        assertEquals(val, MapUtils.getShortValue(in, "noKey", (key)->{
+        assertEquals(val, MapUtils.getShortValue(in, "noKey", key -> {
             return val;
         }), 0);
         assertEquals(0, MapUtils.getShortValue(in, "noKey"), 0);
         assertEquals(val, MapUtils.getShort(in, "key", val), 0);
         assertEquals(val, MapUtils.getShort(in, "noKey", val), 0);
-        assertEquals(val, MapUtils.getShort(in, "noKey", (key)->{
+        assertEquals(val, MapUtils.getShort(in, "noKey", key -> {
             return val;
         }), 0);
 
@@ -1068,13 +1068,13 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals(val, MapUtils.getByteValue(in, "key", val), 0);
         assertEquals(val, MapUtils.getByteValue(in, "key"), 0);
         assertEquals(val, MapUtils.getByteValue(in, "noKey", val), 0);
-        assertEquals(val, MapUtils.getByteValue(in, "noKey", (key) -> {
+        assertEquals(val, MapUtils.getByteValue(in, "noKey", key -> {
             return (byte) 100;
         }), 0);
         assertEquals(0, MapUtils.getByteValue(in, "noKey"), 0);
         assertEquals(val, MapUtils.getByte(in, "key", val), 0);
         assertEquals(val, MapUtils.getByte(in, "noKey", val), 0);
-        assertEquals(val, MapUtils.getByte(in, "noKey", (key)->{
+        assertEquals(val, MapUtils.getByte(in, "noKey", key -> {
             return val;
         }), 0);
 
@@ -1093,7 +1093,7 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
 
         assertEquals(val.intValue(), MapUtils.getNumber(in, "key", val).intValue(), 0);
         assertEquals(val.intValue(), MapUtils.getNumber(in, "noKey", val).intValue(), 0);
-        assertEquals(val.intValue(), MapUtils.getNumber(in, "noKey", (key) -> {
+        assertEquals(val.intValue(), MapUtils.getNumber(in, "noKey", key -> {
             if (true) {
                 return val;
             } else {
@@ -1112,7 +1112,7 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertEquals("str", MapUtils.getString(in, "key"));
         assertEquals(null, MapUtils.getString(null, "key"));
         assertEquals("default", MapUtils.getString(in, "noKey", "default"));
-        assertEquals("default", MapUtils.getString(in, "noKey", (key)->{
+        assertEquals("default", MapUtils.getString(in, "noKey", key -> {
             if ("noKey".equals(key)) {
                 return "default";
             } else {
@@ -1149,22 +1149,22 @@ public class MapUtilsTest extends AbstractAvailableLocalesTest {
         assertTrue(MapUtils.getBooleanValue(in, "key", true));
         assertTrue(MapUtils.getBooleanValue(in, "key"));
         assertTrue(MapUtils.getBooleanValue(in, "noKey", true));
-        assertTrue(MapUtils.getBooleanValue(in, "noKey", (key) -> {
+        assertTrue(MapUtils.getBooleanValue(in, "noKey", key -> {
             return true;
         }));
         assertTrue(!MapUtils.getBooleanValue(in, "noKey"));
         assertTrue(MapUtils.getBoolean(in, "key", true));
         assertTrue(MapUtils.getBoolean(in, "noKey", true));
-        assertTrue(MapUtils.getBoolean(in, "noKey", (key)->{
+        assertTrue(MapUtils.getBoolean(in, "noKey", key -> {
             if (System.currentTimeMillis() > 0) {
                 return true;
             }
             return false;
         }));
-        assertNull(MapUtils.getBoolean(in, "noKey", (key) -> {
+        assertNull(MapUtils.getBoolean(in, "noKey", key -> {
             return null;
         }));
-        assertFalse(MapUtils.getBooleanValue(in, "noKey", (key) -> {
+        assertFalse(MapUtils.getBooleanValue(in, "noKey", key -> {
             return null;
         }));
         assertEquals(null, MapUtils.getBoolean(null, "noKey"));
diff --git a/src/test/java/org/apache/commons/collections4/SplitMapUtilsTest.java b/src/test/java/org/apache/commons/collections4/SplitMapUtilsTest.java
index 04c3d1d93..2359be0a6 100644
--- a/src/test/java/org/apache/commons/collections4/SplitMapUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/SplitMapUtilsTest.java
@@ -41,7 +41,7 @@ public class SplitMapUtilsTest {
     private Map<String, Integer> backingMap;
     private TransformedSplitMap<String, String, String, Integer> transformedMap;
 
-    private final Transformer<String, Integer> stringToInt = input -> Integer.valueOf(input);
+    private final Transformer<String, Integer> stringToInt = Integer::valueOf;
 
     @Before
     public void setUp() throws Exception {
diff --git a/src/test/java/org/apache/commons/collections4/bag/TreeBagTest.java b/src/test/java/org/apache/commons/collections4/bag/TreeBagTest.java
index 4d56fc462..136d747bc 100644
--- a/src/test/java/org/apache/commons/collections4/bag/TreeBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/TreeBagTest.java
@@ -73,7 +73,7 @@ public class TreeBagTest<T> extends AbstractSortedBagTest<T> {
             // expected;
         }
 
-        final Bag<String> bag2 = new TreeBag<>((o1, o2) -> o1.compareTo(o2));
+        final Bag<String> bag2 = new TreeBag<>(String::compareTo);
         try {
             // jdk bug: adding null to an empty TreeMap works
             // thus ensure that the bag is not empty before adding null
diff --git a/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java b/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java
index 30e97cd6d..7507076c9 100644
--- a/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java
@@ -72,7 +72,7 @@ public class LazyMapTest<K, V> extends AbstractIterableMapTest<K, V> {
 
     @Test
     public void mapGetWithTransformer() {
-        final Transformer<Number, Integer> intConverter = input -> input.intValue();
+        final Transformer<Number, Integer> intConverter = Number::intValue;
         final Map<Long, Number> map = lazyMap(new HashMap<Long, Number>(), intConverter);
         assertEquals(0, map.size());
         final Number i1 = map.get(123L);
diff --git a/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java b/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java
index 1097362ba..45416a3a3 100644
--- a/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java
@@ -35,11 +35,11 @@ import org.apache.commons.collections4.functors.NOPTransformer;
 @SuppressWarnings("boxing")
 public class TransformedSplitMapTest extends BulkTest {
 
-    private final Transformer<Integer, String> intToString = input -> String.valueOf(input);
+    private final Transformer<Integer, String> intToString = String::valueOf;
 
     private final Transformer<Object, Class<?>> objectToClass = input -> input == null ? null : input.getClass();
 
-    private final Transformer<String, Integer> stringToInt = input -> Integer.valueOf(input);
+    private final Transformer<String, Integer> stringToInt = Integer::valueOf;
 
     public TransformedSplitMapTest(final String testName) {
         super(testName);