Java short circuit evaluation

Question

I thought Java had short circuit evaluation, yet this line is still throwing a null pointer exception:

if( (perfectAgent != null) && (perfectAgent.ge         


        

Answer 1

If perfectAgent is genuinely null, that code won't throw an exception (at least assuming there aren't weird threading things going on, changing it from non-null to null half way through the expression). I would be utterly shocked if you could produce a short but complete program demonstrating it doing so.

So yes, your intuition is right - this shouldn't be a problem. Look elsewhere for the cause. I strongly suspect that perfectAgent isn't actually null, and that you're running into any of the other situations in that code which could cause an exception.

I suggest you try to extract that bit of code out into a short but complete example - if you can do so, I'll eat my metaphorical hat; if not, you'll hopefully find the problem while you attempt the extraction.

What makes you think that perfectAgent really is null? Try inserting this code before it:

if (perfectAgent == null)
{
    System.out.println("Yup, it's null");
}

Another very, very slim possibility is that you've run into a JIT bug - but I highly doubt it.