Updated Lang3Utils.java (#2584)

* Updated Lang3Utils.java

Added a new test for ConcurrentException and updated other exception with Lambda

* LazyInitializer sample files

* Updated file with LazyInitializer Unit Test

libraries/src/main/java/com/baeldung/commons/lang3/SampleLazyInitializer.java

@@ -0,0 +1,11 @@
+package com.baeldung.commons.lang3;
+
+import org.apache.commons.lang3.concurrent.LazyInitializer;
+
+public class SampleLazyInitializer extends LazyInitializer<SampleObject> {
+    
+    @Override
+    protected SampleObject initialize() {
+        return new SampleObject();
+    }
+}

libraries/src/main/java/com/baeldung/commons/lang3/SampleObject.java

@@ -0,0 +1,7 @@
+package com.baeldung.commons.lang3;
+
+public class SampleObject {
+    
+    //Ignored
+
+}

libraries/src/test/java/com/baeldung/commons/lang3/Lang3UtilsTest.java

@@ -1,6 +1,7 @@
 package com.baeldung.commons.lang3;
 
 import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotSame;
 import static org.junit.Assert.assertSame;
@@ -12,12 +13,14 @@ import java.beans.PropertyChangeListener;
 import java.io.File;
 import java.lang.reflect.Field;
 import java.util.Locale;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 
 import org.apache.commons.lang3.ArchUtils;
 import org.apache.commons.lang3.BooleanUtils;
 import org.apache.commons.lang3.SystemUtils;
 import org.apache.commons.lang3.arch.Processor;
+import org.apache.commons.lang3.concurrent.ConcurrentException;
 import org.apache.commons.lang3.concurrent.ConcurrentRuntimeException;
 import org.apache.commons.lang3.concurrent.ConcurrentUtils;
 import org.apache.commons.lang3.event.EventUtils;
@@ -97,22 +100,37 @@ public class Lang3UtilsTest {
     public void testAddEventListenerThrowsException() {
         final ExceptionEventSource src = new ExceptionEventSource();
         try {
-            EventUtils.addEventListener(src, PropertyChangeListener.class, new PropertyChangeListener() {
+            EventUtils.addEventListener(src, PropertyChangeListener.class, (PropertyChangeEvent e) -> {
-                @Override
+                /* Change event*/});
-                public void propertyChange(final PropertyChangeEvent e) {
-                    // Do nothing!
-                }
-            });
             fail("Add method should have thrown an exception, so method should fail.");
         } catch (final RuntimeException e) {
 
         }
     }
 
+    @Test
+    public void ConcurrentExceptionSample() throws ConcurrentException {
+        final Error err = new AssertionError("Test");
+        try {
+            ConcurrentUtils.handleCause(new ExecutionException(err));
+            fail("Error not thrown!");
+        } catch (final Error e) {
+            assertEquals("Wrong error", err, e);
+        }
+    }
+
     public static class ExceptionEventSource {
         public void addPropertyChangeListener(final PropertyChangeListener listener) {
             throw new RuntimeException();
         }
     }
 
+    @Test
+    public void testLazyInitializer() throws Exception {
+        SampleLazyInitializer sampleLazyInitializer = new SampleLazyInitializer();
+        SampleObject sampleObjectOne = sampleLazyInitializer.get();
+        SampleObject sampleObjectTwo = sampleLazyInitializer.get();
+        assertEquals(sampleObjectOne, sampleObjectTwo);
+    }
+
 }