28bc1070e7
Motivation: As reported in #4211, when using Netty in Tomcat (or other container based deployment), ForkJoinPool leaks an instance of `Submitter` so that the class loader of `Submitter` won't be GCed. However, since `Submitter` is just a wrapper of `int`, we can replace it with `int[1]`. Modifications: Replace `Submitter` with `int[1]`. Result: No class loader leak in ForkJoinPool when using in a container.