6. Static Attributes

• Static attributes are shared by all objects instantiated for a given class.

• This means that only a single copy of static attribute is allocated in memory.

  
      public class ClassicSingleton {
  
          private static ClassicSingleton instance = null;
  
          protected ClassicSingleton() {
              // Exists only to defeat instantiation.
          }
  
          public static ClassicSingleton getInstance() {
              if( instance == null ) {
                  instance = new ClassicSingleton();
              }
              return instance;
          }
      }