The JDK ships with a plethora of command line applications. Some of these utilities we use everyday without much thought: the ubiquitous java, javac and jar commands for example. Others, we completely ignore as anarchisms: use appletviewer lately? Most of these applications, however, remain almost invisible, hiding inconspicuously in the bowels of the JDK directory structure. Yet these under appreciated tools contain some powerful functionality for troubleshooting, monitoring and analysis of applications on the JVM. Tools such as jcmd, jstat, jmap, jhat among others should be in the ready arsenal of every Java (or any JVM language) poweruser. Let’s take a look at how you can utilize these utilities and make them a part of your JVM toolbox.