Don't subclass ThreadLocal.
Don't subclass ThreadLocal.

This attempts to address issue 402, wherein subclassing ThreadLocal is pinning a reference to a class, which transitively pins the entire application in containers like Tomcat.

testcenter/gson,DanySK/gson-extras,mbrukman/gson,DanySK/gson-extras,gv2011/jsoncore,testcenter/gson,google/gson,mbrukman/gson,mbrukman/gson,testcenter/gson,todoooo/gson,DanySK/gson-extras,todoooo/gson,todoooo/gson