Findbugs says:

Bug: org.apache.jasper.runtime.JspFactoryImpl$PageContextPool needs to be _static_ to avoid a deadly embrace with org.apache.jasper.runtime.JspFactoryImpl.localPool
Pattern id: SIC_THREADLOCAL_DEADLY_EMBRACE, type: SIC, category: CORRECTNESS


This class is an inner class, but should probably be a static inner class. As it is, there is a serious danger of a deadly embrace between the inner class and the thread local in the outer class. Because the inner class isn't static, it retains a reference to the outer class. If the thread local contains a reference to an instance of the inner class, the inner and outer instance will both be reachable and not eligible for garbage collection.