A singleton pattern from Spring in Action 3rd

00.Singleton Pattern in Spring

title file

Stage.java

public class Stage {
  private Stage() {
    
  } 
  // Lazily loads instance
  privatestaticclassStageSingletonHolder{
    staticStageinstance=newStage();
  }
  public staticStagegetInstance(){
    returnStageSingletonHolder.instance;
  }
}