BAEL-2770 Added code and test cases

core-java-arrays/src/main/java/com/baeldung/array/AddElementToEndOfArray.java

@@ -0,0 +1,34 @@
+package com.baeldung.array;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+public class AddElementToEndOfArray {
+
+    public Integer[] addElementUsingArraysCopyOf(Integer[] srcArray, int elementToAdd) {
+        Integer[] destArray = Arrays.copyOf(srcArray, srcArray.length + 1);
+
+        destArray[destArray.length-1] = elementToAdd;
+        return destArray;
+    }
+
+    public Integer[] addElementUsingArrayList(Integer[] srcArray, int elementToAdd) {
+        Integer[] destArray = new Integer[srcArray.length + 1];
+
+        ArrayList<Integer> arrayList = new ArrayList<>(Arrays.asList(srcArray));
+        arrayList.add(elementToAdd);
+
+        return arrayList.toArray(destArray);
+    }
+
+    public Integer[] addElementUsingSystemArrayCopy(Integer[] srcArray, int elementToAdd) {
+        Integer[] destArray = new Integer[srcArray.length + 1];
+
+        System.arraycopy(srcArray, 0, destArray, 0, srcArray.length);
+
+        destArray[destArray.length-1] = elementToAdd;
+
+        return destArray;
+    }
+
+}

core-java-arrays/src/test/java/com/baeldung/array/AddElementToEndOfArrayUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.array;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class AddElementToEndOfArrayUnitTest {
+
+    AddElementToEndOfArray addElementToEndOfArray;
+
+    @Before
+    public void init(){
+        addElementToEndOfArray = new AddElementToEndOfArray();
+    }
+
+    @Test
+    public void givenSourceArrayAndElement_whenAddElementUsingArraysCopyIsInvoked_thenNewElementMustBeAdded(){
+        Integer[] sourceArray = {1,2,3,4};
+        int elementToAdd = 5;
+
+        Integer[] destArray = addElementToEndOfArray.addElementUsingArraysCopyOf(sourceArray, elementToAdd);
+
+        assertEquals(elementToAdd, destArray[destArray.length-1].intValue());
+    }
+
+    @Test
+    public void givenSourceArrayAndElement_whenAddElementUsingArrayListIsInvoked_thenNewElementMustBeAdded(){
+        Integer[] sourceArray = {1,2,3,4};
+        int elementToAdd = 5;
+
+        Integer[] destArray = addElementToEndOfArray.addElementUsingArrayList(sourceArray, elementToAdd);
+
+        assertEquals(elementToAdd, destArray[destArray.length-1].intValue());
+    }
+
+    @Test
+    public void givenSourceArrayAndElement_whenAddElementUsingSystemArrayCopyIsInvoked_thenNewElementMustBeAdded(){
+        Integer[] sourceArray = {1,2,3,4};
+        int elementToAdd = 5;
+
+        Integer[] destArray = addElementToEndOfArray.addElementUsingSystemArrayCopy(sourceArray, elementToAdd);
+
+        assertEquals(elementToAdd, destArray[destArray.length-1].intValue());
+    }
+}