How to stop creating instance of Singleton

Question

I have a Singleton class like this:

class Singleton {
    static class SingletonHolder {
        static final Singleton INSTANCE = new Singleton();
    }
    public static Singleton getInstance() {
        return SingletonHolder.INSTANCE;
    }
}

Can I call like this from other class:

Singleton dummy = new Singleton();

if yes how can I disable it? if not, then why cannot i?

Louis Wasserman · Accepted Answer · 2015-05-11 23:03:30Z

7

Sure. Just make the constructor private to avoid that: just add private Singleton() {} to prevent the default constructor from being public.

answered May 11, 2015 at 23:03

Louis Wasserman

200k26 gold badges367 silver badges437 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Elliott Frisch · Accepted Answer · 2015-05-11 23:09:01Z

3

I suggest you make it an enum (since they can't be instantiated anyway);

enum Singleton {
    INSTANCE;
    public static Singleton getInstance() {
        return INSTANCE;
    }
}

answered May 11, 2015 at 23:09

Elliott Frisch

202k20 gold badges166 silver badges265 bronze badges

1 Comment

ZhongYu Over a year ago

well I'm against using enum for singleton. but it has been discussed too many times:)

Collectives™ on Stack Overflow

How to stop creating instance of Singleton

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related