Singlton

While writing the Singleton class I would consider these things

• Make the default constructor private.
• Create a static and public getInstance method returning the object of the singleton class.
• Make the class final.
• Implement the Cloneable interface.
• Override the clone method to throw the CloneNotSupportedException.

package test.patterns; public final class Singlton implements Cloneable { private static Singlton singlton = null; private Singlton(){} public static Singlton getInstance(){     if(singlton == null){         singlton = new Singlton();     }     return singlton; }     protected Object clone() throws CloneNotSupportedException {         throw new CloneNotSupportedException ("I do not allow to clone, this is SINGLTON");     } }

used Java2html to format the code

The other good type I read in the "Spring in Action" book

package test.patterns;

public class SingltonInner {

  private SingltonInner(){}
  
  private static class InnerSingltonInstance{
    static SingltonInner singlton = new SingltonInner();
  }
  
  public static SingltonInner getInstance(){
    return InnerSingltonInstance.singlton;
  }
}








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