The previous post about JVM turned out to be well-received, so I would like to uncover another fun topic related to JVM - Java agents. Although not everyone gets a chance to write custom Java agents in his career, they are still a wonderful field to explore and open an endless way to customize JVM behavior. Java agents are special in the way that JVM allows them to do much more than a regular Java app is allowed to: they can instrument or profile code, hot-swap classes, patch methods, etc.
