FilesExpand file tree

master

/

SingletonBreaksCloning.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

54 lines (46 loc) · 1.51 KB

master

/

SingletonBreaksCloning.java

Copy path

Top

File metadata and controls

• Code
• Blame

54 lines (46 loc) · 1.51 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

package com.java;

class SuperClass implements Cloneable {

int i = 10;

@Override

protected Object clone() throws CloneNotSupportedException {

return super.clone();

}

}

// Singleton class

class Singletonc extends SuperClass{

// public instance initialized when loading the class

public static Singletonc instance = new Singletonc();

private Singletonc() {

// private constructor

}

}

public class SingletonBreaksCloning {

public static void main(String[] args) throws CloneNotSupportedException {

Singletonc instance1 = Singletonc.instance;

Singletonc instance2 = (Singletonc) instance1.clone();

System.out.println("instance1 hashCode:- "

+ instance1.hashCode());

System.out.println("instance2 hashCode:- "

+ instance2.hashCode());

}

}

// To overcome this issue, override clone() method and throw an exception from clone method

// that is CloneNotSupportedException.

// Now whenever user will try to create clone of singleton

// object, it will throw exception and hence our class remains singleton.

// Singleton class

class Singletoncc extends SuperClass

{

// public instance initialized when loading the class

public static Singletoncc instance = new Singletoncc();

private Singletoncc()

{

// private constructor

}

@Override

protected Object clone() throws CloneNotSupportedException

{

throw new CloneNotSupportedException();

//or return instance;

}

}