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Java Singleton Class Example Using Private Constructor

  • We can make constructor as private. So that We can not create an object outside of the class.
  • This property is useful to create singleton class in java.
  • Singleton pattern helps us to keep only one instance of a class at any time.
  • The purpose of singleton is to control object creation by keeping private constructor.

Java Singleton Sample Code

package com.myjava.constructors;

public class MySingleTon {
    private static MySingleTon myObj;
     * Create private constructor
    private MySingleTon(){
     * Create a static method to get instance.
    public static MySingleTon getInstance(){
        if(myObj == null){
            myObj = new MySingleTon();
        return myObj;
    public void getSomeThing(){
        // do something here
        System.out.println("I am here....");
    public static void main(String a[]){
        MySingleTon st = MySingleTon.getInstance();

Other Constructor Examples

Knowledge Centre
Can we call servlet destory() from service()?
As you know, destory() is part of servlet life cycle methods, it is used to kill the servlet instance. Servlet Engine is used to call destory(). In case, if you call destory method from service(), it just execute the code written in the destory(), but it wont kill the servlet instance. destroy() will be called before killing the servlet instance by servlet engine.
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About Author

I'm Nataraja Gootooru, programmer by profession and passionate about technologies. All examples given here are as simple as possible to help beginners. The source code is compiled and tested in my dev environment.

If you come across any mistakes or bugs, please email me to [email protected].

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Reference: Java™ Platform Standard Ed. 7 - API Specification | Java™ Platform Standard Ed. 8 - API Specification | Java is registered trademark of Oracle.
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