There is no Spoon: Changing Final Fields in Java

21. January, 2013

If you’re the guy in the team who solves the impossible problems, you will eventually run into the worst of all design patterns: Singletons. Which are implemented in Java using final (static) fields.

Sebastian Zarnekow came up with a way to change that. Following the timeless advice from the Matrix – there is no spoon -, he found a way to modify (some) final fields.

As I said before, this is a desperate measure, so use it wisely. But remember this tool next time when you need to mock a singleton for a test case.