ThreadLocalNotStaticFinal.md

Pattern: ThreadLocal not static and final

Issue: -

Description

This rule reports definition of the ThreadLocal fields that are not static and final.

ThreadLocal fields should be static and final. In the most common case a java.lang.ThreadLocal instance associates state with a thread. A non-static non-final java.lang.ThreadLocal field associates state with an instance-thread combination. This is seldom necessary and often a bug which can cause memory leaks and possibly incorrect behavior.

Here is an example of code that produces a violation:

private static ThreadLocal local1 = new ThreadLocal()
private final ThreadLocal local2 = new ThreadLocal()
protected ThreadLocal local3 = new ThreadLocal()
ThreadLocal local4 = new ThreadLocal()

Further Reading

• CodeNarc - ThreadLocalNotStaticFinal