The Pragmatic Craftsman :: Simplicity from complexity ::

Are you using them?

I only found out about them recently — they’ve been available since JDK 1.4. I think they’re vastly underutilized…. But they can be really helpful in debugging situations and don’t incur any performance hit.

You can enable them in your JDK by adding “-enableassertions” to default VM arguments (type “jre” in filters in Eclipse and edit it there).

Then in your code, whenever you have a feeling “this can never be null or false” add the assertion, as inassert thisField != null; and you’re done.

Assertions are a great debugging tool.