Cloneable Interface in Java

Last Updated : 8 Oct, 2025

In Java, the Cloneable interface is a marker interface used to indicate that a class allows creating an exact copy of its objects. It is part of java.lang package and is primarily used with the Object.clone() method to create duplicates of objects.

It does not contain any methods (Marker Interface).
Its main purpose is to signal to the Object.clone() method that the objects of this class can be safely cloned.
If a class implements Cloneable, calling clone() on its objects will create a shallow copy.

Syntax

class ClassName implements Cloneable {
// class fields and methods
}

Example 1: Basic Shallow Cloning

This example shows how to create a shallow copy using the Cloneable interface and clone() method, we achieve shallow cloning by simply calling super.clone().

Output

Original: Alice, 25
Clone: Alice, 25
After modification:
Original: Alice
Clone: Bob

Explanation:

The clone() method creates a copy of the object.
Modifying the clone does not affect the original object because each object has its own memory.
Cloneable is a marker interface that signals Object.clone() can safely copy the object.

Example 2: Deep Copy Example

This example demonstrates a deep copy in Java, where the object and its nested objects are fully duplicated, so changes to the clone do not affect the original.

Output

Original City: New York
Clone City: London

Advantages of Using Cloneable

Easy Object Copying: Simplifies creation of object copies.
Improves Performance: Faster than manually creating a new object and copying all fields.
Customizable Cloning: Can implement shallow or deep cloning as needed.
Useful in Prototyping: Quickly generate copies of objects without reinitializing them.