I'm using iBatis in a webapp with Spring and facing memory leaks upon redeployment oft he webapp.
I tracked the leaks to ibatis, where the class ResultObjectFactoryUtil has a static ThreadLocal factorySettings
The problem is that the value bound to a Thread through this ThreadLocal is never nullified, and since the "factorySettings" is a static variable, the ThreadLocal instance is reachable as long as the ClassLoader of the webapp is reachable. But since the FactorySettings instance is bound to the Thread through a strong reference (see the JDK implementation of ThreadLocal in ThreadLocalMap$Entry), the classloader is finally never collected...
The solution is to always cleanup the ThreadLocal after usage (in SqlExecurtor)
I attach a patch for iBatis 2.3.4 to this issue