kongcurrent provides an easy-to use helper to assist debugging issues which cause exceptions under concurrent access. It was inspired by a problem in which a non-thread-safe Map object held by a third party framework was accidentally shared between threads, causing a ConcurrentModificationException. The helper (a "monitor") creates a proxied version of an object implementing some interface. The proxy can track invocations of the objects' methods and can report on potential concurrent access on the object. This can be used to help find code paths which concurrently access the object through its interface methods. By design, the helper is extensible, and can be adapted to more specific needs.
Executor is a small but perfectly functional Java (1.5 or higher) JAR executable that is used to run programs in shared computer resources like a pool of computers that you and your friends own. Moreover, it can be used as a simple file sharing program: you can access the files of your home computer from your office computer. Executor uses a shared or synchronized file system. The user creates a task in one computer (just by uploading a file), and another computer that has the required program will execute the task.