Modified code for Test

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/shallowdeepcopy/School.java

@@ -0,0 +1,22 @@
+package com.baeldung.shallowdeepcopy;
+
+class School {
+    private String schoolName;
+    public School(School sc) {
+       this(sc.getSchoolName());
+    } 
+    public School(String schoolName) { 
+        this.schoolName = schoolName; 
+    } 
+    // standard getters and setters 
+}
+
+@Override
+public Object clone() { 
+    try { 
+        return (School) super.clone();
+    } catch (CloneNotSupportedException e) { 
+        return new School(this.getSchoolName()); 
+    } 
+}
+

core-java-modules/core-java-lang-oop-patterns/src/main/java/com/baeldung/shallowdeepcopy/Student.java

@@ -14,3 +14,14 @@ class Student {
     } // standard getters and setters 
 }
 
+@Override 
+public Object clone() {
+    Student student = null;
+    try {
+        student = (Student) super.clone();
+    } catch (CloneNotSupportedException e) {
+        student = new Student(this.getName(), this.getAge(), this.getSchool());
+    } 
+    student.school= (School) this.school.clone();
+    return student; 
+}

core-java-modules/core-java-lang-oop-patterns/src/test/java/com/baeldung/shallowdeepcopy/ShallowDeepCopyExampleTest.java

@@ -6,29 +6,36 @@ import org.junit.jupiter.api.Test;
 public class ShallowDeepCopyExampleTest {
 	
     @Test 
-	void testShallowCopy() {
+    public void whenPerformShallowCopy_thenObjectsNotSame() { 
-		Student originalStudent = new Student("John", 20);
+        School school = new School("Baeldung School");
-		Student shallowCopy = originalStudent;
+        Student originalStudent = new Student("John", 20, school); 
+        Student shallowCopy = new Student(originalStudent.getName(), originalStudent.getAge(), originalStudent.getSchool());
+        assertNotSame(shallowCopy, originalStudent); 
+    }
 
-		shallowCopy.setName("Baeldung");
+    @Test public void whenModifyingActualObject_thenCopyAlsoChange() { 
-		shallowCopy.setRollno(10);
+        School school = new School("Baeldung School"); 
-
+        Student originalStudent = new Student("John", 20, school); 
-		assertEquals("Baeldung", originalStudent.getName());
+        Student shallowCopy = new Student(originalStudent.getName(), originalStudent.getAge(), originalStudent.getSchool()); 
-		assertEquals(10, originalStudent.getRollno());
+        school.setSchoolName("New Baeldung School"); 
+        assertEquals(shallowCopy.getSchool().getSchoolName(), originalStudent.getSchool().getSchoolName());
     }
 
 	@Test
-    void testDeepCopy() {
+    public void whenModifyingActualObject_thenCloneCopyNotChange() { 
-        Student originalStudent = new Student("John", 20);
+        School school = new School("New School");
-        Student deepCopy = new Student(originalStudent.getName(), originalStudent.getRollno());
+        Student originalStudent = new Student("Alice", 10, school); 
+        Student deepCopy = (Student) originalStudent.clone(); 
+        school.setSchoolName("New Baeldung School"); 
+        assertNotEquals(deepCopy.getSchool().getSchoolName(), originalStudent.getSchool().getSchoolName()); 
+    }
 
-        deepCopy.setName("Baeldung");
+    @Test 
-        deepCopy.setRollno(10);
+    public void whenModifyingActualObject_thenCopyNotChange() {
-
+        School school = new School("Baeldung School");
-        assertEquals("John", originalStudent.getName());
+        Student originalStudent = new Student("Alice", 30, school); 
-        assertEquals(20, originalStudent.getRollno());
+        Student deepCopy = new Student(originalStudent); 
-
+        school.setSchoolName("New Baeldung School"); 
-        assertEquals("Baeldung", deepCopy.getName());
+        assertNotEquals( originalStudent.getSchool().getSchoolName(), deepCopy.getSchool().getSchoolName()); 
-        assertEquals(10, deepCopy.getRollno());
     }
 }