单例模式

 饿汉式单例类
public class EagerSingleton{
    private static final EagerSingleton m_instance=new EagerSingleton();
    /**
     私有的默认构造子
   **/
  private EagerSingleton(){}

  public static EagerSingleton getInstance(){
         return m_instance;

   }
}

懒汉式单例类
public class LazySingleton{
   private static LazySingleton l_instance=null;
  
   private LazySingleton(){}

  synchronized public static LazySingleton getInstance(){
      if(l_instance==null){

        l_instance=new LazySingleton();
      }
     return l_insatnce;

}
  

}