More on Nullness

The other day I wrote about using annotations to state your intent regarding null for fields, parameters and return values. This can help static checkers like findbugs find flaws in your code, where you fail to check return values for null where that is known to be risky. (In fact, findbugs does not only base knowledge of nullness on your use of annotations; it also has a builtin database of system API null behaviors, since these classes have not been "instrumented" with nullness annotations yet.) I did however mention one big problem: These annotations are not (yet) standard - so you'll need to choose to use them from somewhere - and add third party imports to all your source files, add a foreign jar to your build, etc. Findbugs' set of annotations is probably as good a candidate as any. But while the annotations are licensed under LGPL, which should be fine for most of us, some companies (or at least their lawyers) are weary of mixing GPL anything with proprietary code. Our lawyers are generally fine with LGPL usage, but I was still wondering if there was a way I could "isolate" myself by using an annotation from my own project, and then somehow tie that to a standard annotation in a single place. If annotations were like classes this would be easy - I could simply extend the findbugs one and I'd be done. But annotations don't work that way. So I thought I'd take a look at findbugs internals and see what's going o...

Date: August, 25 2006
Url: http://blogs.sun.com/tor/entry/more_on_nullness

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