How do you prevent for creating another instance of Singleton using clone() method in java?

The class will need to implement the clone() mehod as below:

public class Singleton {

    private static final Singleton singleton = new Singleton();

    private Singleton() { }

    public static Singleton getInstance(){

        return singleton;

    }

    @Override

    protected Object clone() throws CloneNotSupportedException {

        throw new CloneNotSupportedException("Cloning of this class is not allowed"); 

    }

}

If your class which is based on the Singleton pattern does not implement the Cloneable interface then the clone() method cannot be called on that object.