How to Create Singleton Class in Java, Singleton Class in Java

Core Java » On Sep 29, 2012 By Sivateja

Making java class as singleton is very important in some real time projects, we may need to have exactly one instance of a class. Suppose in hibernate  SessionFactory should be singleton as its heavy weight, and some other Banking related projects mainly.

Some times creating singleton classes are very very important, if we are creating the object of some classes again and again ‘N’ number of times, that will definitely kills the memory and finally our application will get down, so we can avoid that with this concept.

Let us see how to..

Files required

  • AccountCreation.java
  • Client.java

AccountCreation.java

Client.java

Output

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Comments

20 Responses to “How to Create Singleton Class in Java, Singleton Class in Java”
  1. Pavan says:

    Sir,please can u explain the AccountCreation.java program?
    thanks..,

  2. suresh says:

    Hi,
    You should provide private constructor to “AccountCreation” class. Otherwise user can create new instance for that.
    Thanks,
    Suresh.p

  3. Java4s says:

    @Suresh

    I Agree :-)

  4. Srinivasa says:

    @Suresh

    I Agree with you..

  5. the above class should implement cloneable interface otherwise we can clone object i.e we can create duplicate object for class

  6. Ishwar Kumar says:

    What is difference between enumration and abstract class

  7. Bhushan says:

    Hi Sir,

    Please provide some explanations of Design Patterns also.

  8. satya says:

    @Suresh. I agree with you. We need to create private constructor.

  9. Arshi says:

    how to prevent cloning of singleton class?

  10. thasil says:

    @loshith kumar

    we should not implement cloneable

    @java4s

    we should use synchronized in object creation section not in method

  11. Anuradha says:

    sir
    plz tell me some concepts of creating writing reading from file in java

  12. Satish says:

    Sir , if we place this singleton class in to web project and deploye at same time then jvm well create two object for this singleton class how we can avoid thise.

  13. pavan says:

    sir, please add few more core java real time scenarios like these. Awesome site sir.

  14. Ramesh says:

    Sir,It is possible to create private static instance variables how it will can you explain sir private means we can use with in the block only static means we can use any where in the program how it will be possible can you explain sir please………

  15. Renjith says:

    Can you give an example for multiple object creation for any java program?
    Also
    If my understanding is correct,to achieve singleton pattern synchronization is not required.
    The same program we could write it without using the synchronized keyword.

  16. madhu says:

    Hi Sir
    I know Factory DesignPattern but in real time why you design in HealthCare and Banking domain

  17. Rambabu says:

    Hi,

    While in de-serialization of the above AccountCreation instance , every time we will get new object. How to avoid it?

  18. Anil says:

    1)in this program one problem is their,two threads try to create objs that time one obj wait until second obj release the lock.
    if already obj created by second thread why again first thread take lock

  19. pullarao says:

    Can You Please Give me Some Other Example without using Synchronization Sir

  20. rijesh says:

    Can You Please Give me Some Example for ip address validation sir???

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