Tom Copeland has released PMD 3.5, an open source tool for automatically checking Java code for various classes of bugs. Version 3.5 adds twelve new rules including:
- UselessOperationOnImmutable
- MisplacedNullCheck
- UnusedNullCheckInEquals
- IntegerInstantiation
- UseAssertNullInsteadOfAssertTrue
- AppendCharacterWithChar
- ConsecutiveLiteralAppends
- UseIndexOfChar
- AvoidConstantsInterface
- UseArraysAsList
- AvoidArrayLoops
- BooleanInversion
Some of the optimizations suggested strike me as extremely questionable, and may well be the result of naive benchmarking.
I've been doing some new work on XOM 1.2 lately, and there's quite a bit of code in the current CVS that hasn't previously been tested by this sort of tool, so I ran it on XOM. My initial runs hit some out of memory errors, so I tried it one ruleset at a time. The new rule to "Avoid concatenating characters as strings in StringBuffer.append" found a couple of places I could fix. ConsecutiveLiteralAppends only found false positives that I could see. It's a little buggy. The basic ruleset took a long time to run, but didn't find anything important. The other new rules didn't catch anything either.