[is-object-array] Check if Object is an Array in Java (#13463)

core-java-modules/core-java-arrays-operations-basic/src/test/java/com/baeldung/array/isobjectarray/CheckObjectIsArrayUnitTest.java

@@ -0,0 +1,78 @@
+package com.baeldung.array.isobjectarray;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.lang.reflect.Array;
+
+import org.junit.jupiter.api.Test;
+
+public class CheckObjectIsArrayUnitTest {
+    private static final Object ARRAY_INT = new int[] { 1, 2, 3, 4, 5 };
+    private static final Object ARRAY_PERSON = new Person[] { new Person("Jackie Chan", "Hong Kong"), new Person("Tom Hanks", "United States") };
+
+    boolean isArray(Object obj) {
+        return obj instanceof Object[] || obj instanceof boolean[] || obj instanceof byte[] || obj instanceof short[] || obj instanceof char[] || obj instanceof int[] || obj instanceof long[] || obj instanceof float[] || obj instanceof double[];
+    }
+
+    @Test
+    void givenAnArrayObject_whenUsingInstanceof_getExpectedResult() {
+        assertTrue(ARRAY_PERSON instanceof Object[]);
+        assertFalse(ARRAY_INT instanceof Object[]);
+        assertTrue(ARRAY_INT instanceof int[]);
+    }
+
+    @Test
+    void givenAnArrayObject_whenUsingOurIsArray_getExpectedResult() {
+        assertTrue(isArray(ARRAY_PERSON));
+        assertTrue(isArray(ARRAY_INT));
+    }
+
+    @Test
+    void givenAnArrayObject_whenUsingClassIsArray_getExpectedResult() {
+        assertTrue(ARRAY_INT.getClass()
+          .isArray());
+        assertTrue(ARRAY_PERSON.getClass()
+          .isArray());
+
+        assertEquals(Person.class, ARRAY_PERSON.getClass()
+          .getComponentType());
+        assertEquals(int.class, ARRAY_INT.getClass()
+          .getComponentType());
+
+    }
+
+    @Test
+    void givenAnArrayObject_whenUsingArrayGet_getExpectedElement() {
+        if (ARRAY_PERSON.getClass()
+          .isArray() && ARRAY_PERSON.getClass()
+          .getComponentType() == Person.class) {
+            Person person = (Person) Array.get(ARRAY_PERSON, 1);
+            assertEquals("Tom Hanks", person.getName());
+        }
+        if (ARRAY_INT.getClass()
+          .isArray() && ARRAY_INT.getClass()
+          .getComponentType() == int.class) {
+            assertEquals(2, ((int) Array.get(ARRAY_INT, 1)));
+        }
+    }
+}
+
+class Person {
+    private String name;
+    private String Location;
+
+    public Person(String name, String location) {
+        this.name = name;
+        this.Location = location;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getLocation() {
+        return Location;
+    }
+}