[BAEL-6960] value based class (#14785)

* [BAEL-6960] value based class

* [BAEL-6960] value based class

* [BAEL-6960] value based class

---------

Co-authored-by: Bhaskar <bhaskar.dastidar@freshworks.com>

core-java-modules/core-java-16/src/main/java/com/baeldung/value_based_class/Point.java

@@ -0,0 +1,49 @@
+package com.baeldung.value_based_class;
+
+import java.util.Objects;
+
+import jdk.internal.ValueBased;
+
+/**
+ * This class is written with the intention that it can serve as an example of
+ * what a Value-based class could be.
+ */
+
+@ValueBased
+public final class Point {
+    private final int x;
+    private final int y;
+    private final int z;
+
+    private static Point ORIGIN = new Point(0, 0, 0);
+
+    private Point(int x, int y, int z) {
+        this.x = x;
+        this.y = y;
+        this.z = z;
+    }
+
+    public static Point valueOfPoint(int x, int y, int z) {
+        // returns a cached instance if it is origin, or a new instance
+        if (isOrigin(x, y, z))
+            return ORIGIN;
+        return new Point(x, y, z);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other == null || getClass() != other.getClass())
+            return false;
+        Point point = (Point) other;
+        return x == point.x && y == point.y && z == point.z;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(x, y, z);
+    }
+
+    private static boolean isOrigin(int x, int y, int z) {
+        return x == 0 && y == 0 && z == 0;
+    }
+}

core-java-modules/core-java-16/src/test/java/com/baeldung/value_based_class/ValueBasedClassUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.value_based_class;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ValueBasedClassUnitTest {
+    @Test
+    public void givenAutoboxedAndPrimitive_whenCompared_thenReturnEquals() {
+        int primitive_a = 125;
+        Integer obj_a = 125; // this is autoboxed
+        Assert.assertSame(primitive_a, obj_a);
+    }
+
+    @Test
+    public void givenValueBasedPoint_whenCreated_thenReturnsObjects() {
+        Point p1 = Point.valueOfPoint(1, 2, 3);
+        Point p2 = Point.valueOfPoint(2, 3, 4);
+
+        Assert.assertNotEquals(p1, p2);
+    }
+
+    @Test
+    public void givenValueBasedPoint_whenCompared_thenReturnEquals() {
+        Point p1 = Point.valueOfPoint(1, 2, 3);
+        Point p2 = Point.valueOfPoint(1, 2, 3);
+
+        Assert.assertEquals(p1, p2);
+    }
+
+    @Test
+    public void givenValueBasedPoint_whenOrigin_thenReturnCachedInstance() {
+        Point p1 = Point.valueOfPoint(0, 0, 0);
+        Point p2 = Point.valueOfPoint(0, 0, 0);
+        Point p3 = Point.valueOfPoint(1, 2, 3);
+
+        // the following should not be assumed for value-based classes
+
+        Assert.assertTrue(p1 == p2);
+        Assert.assertFalse(p1 == p3);
+    }
+}