This template can be used to automatically add all the singleton code to your class. To add it do the following:

First goto Window->Preferences and then on the left side go to Java->Editor->Templates. Now click on New and fill in the following information:

And copy the following code into the Pattern field:

  /**
   * Instance variable containing the singelton reference.
   */
  private static ${enclosing_type} instance = null;

  /**
   * Private constructor so that this object cannot be instantiated.
   */
  private ${enclosing_type}() {
    // Initialization code goes here.
  }

  /**
   * Method for retrieving the singleton instance of the <code>${enclosing_type}</code> class.
   *
   * @return a reference to the singleton instance.
   */
  public static synchronized ${enclosing_type} getInstance() {
    if (instance == null) {
      instance = new ${enclosing_type}();
    }

    return instance;
  }

  ${cursor}

  /**
   * Disable cloning since this is not supported for singleton classes.
   */
  public Object clone() throws CloneNotSupportedException {
    throw new CloneNotSupportedException();
  }

Now press OK and the template is stored.

To use the template do the following, create a new class without any code, go with the cursor inside the class and type 'singleton', now press CTRL + SPACE and select the 'singleton' template. Now you should have all the code for the singleton.