#fixed code
                             public void start() {
		if( selectorthread != null )
			throw new IllegalStateException( "Already started" );
		new Thread( this ).start();
	}
#vulnerable code 
                             public void start() {
		if( thread != null )
			throw new IllegalStateException( "Already started" );
		new Thread( this ).start();
	} 
                            #location 2 
                            #vulnerability type THREAD_SAFETY_VIOLATION