if( instanceId == null ) { throw new NullPointerException( "instanceId" ); }  this.instanceId = instanceId;
    public DefaultContextFactoryService()    {        // Register shutdown hook.        Runtime.getRuntime().addShutdownHook( new Thread( new Runnable() {            public void run()            {                try                {                    shutdown();                }                catch( NamingException e )                {                    e.printStackTrace();                }            }        }, "ApacheDS Shutdown Hook" ) );    }