Burnt by Java assert Again

I was debugging a problem in jSuneido and I put in an assert that I was pretty sure would fail. It didn't.

I changed it to "assert false" just to be sure. It still didn't fail. WTF

I went back to my last blog post about this (Don't Forget to enable Java assert) because I couldn't remember how I'd fixed this. (Half the reason I blog is so I have a record for my own use!)

Oh yeah, I'd set the Default VM Arguments (to -ea). Why did that get lost?

Because I installed Snow Leopard, which finally came with a 1.6 JRE, which I'd switched to using.

Easy enough to add the setting again, but how can I avoid getting burnt by this again?

Of course, the same way you avoid a bug recurring - by writing a test.

My first attempt was the standard way to test that something throws:

        try {

            assert false;

            fail("assert not enabled");

        } catch (AssertionError e) {

        }

But that succeeded with or without the -ea setting!?  It took me a few minutes of head scratching to realize that fail also throws AssertionError so I had to do:

        try {

            assert false;

        } catch (AssertionError e) {

            return;

        }

        fail("assert not enabled");

At least now I'll know right away (or at least the first time I run the tests) if I lose assert again.

I still think the default should be to enable assert, at least for development. (The higher performance server VM could disable assert by default.) Even if Java itself didn't do this, Eclipse could.