Is there a race condition in this code?

[Pho Tek]

    
1    private final WeakReference<RemoteCommunicationHandler> m_handlerRef;
 
2    public void registerForUpdatesToNodeWithUri( String uri )
3    {
5        synchronized( m_handlerRef )
6        {
7            RemoteCommunicationHandler handler = null;
8            if( ( handler = m_handlerRef.get() ) == null )
9                return;
10
11           handler.requestUpdates( m_producer, uri );
12       }
13   }

Is there a chance of me getting a NullPointerException between the lines
8 to 11 ? This might be a stupid question. Bear with me. Thanks

[Jim Yingst]

No.

[Pho Tek]

Now I can sleep well at night. Thanks Jim.

[Peter Chase]

The initialisation of "handler" to null is unnecessary.

Generally, one should not initialise variables except when the algorithm really requires it. Unnecessary initialisations: -

bloat the code

defeat the useful feature of the compiler that checks whether variables are initialised before they are used

[Pho Tek]

Peter, good point!

[Gladwin Burboz]

You can get NullPointerExecption at line 5 if m_handlerRef is null

[Jim Yingst]

Yes, but since m_handlerRef is final, the compiler must have forced the programmer to initialize the variable in a constructor or something, not shown here. It's possible that for some reason it's been initialized to null, but that's hardly a race condition - it's a fundamental problem with the program that will be very obvious as soon as it appears. Race conditions are generally much more elusive.

[Pho Tek]

@Gladwin,

m_handlerRef is assigned a value in the constructor for the class.
So it can't ever be null.
[ March 10, 2008: Message edited by: Pho Tek ]