By Alvin Alexander. Last updated: June 4, 2016
This JConsole page has some nice Java/JVM garbage collector terminology, including the following definitions:
- Eden Space (heap): The pool from which memory is initially allocated for most objects.
- Survivor Space (heap): The pool containing objects that have survived the garbage collection of the Eden space.
- Tenured Generation (heap): The pool containing objects that have existed for some time in the survivor space.
- Permanent Generation (non-heap) (permgen): The pool containing all the reflective data of the virtual machine itself, such as class and method objects. With Java VMs that use class data sharing, this generation is divided into read-only and read-write areas.
- Code Cache (non-heap): The HotSpot Java VM also includes a code cache, containing memory that is used for compilation and storage of native code.
These other articles are also very helpful if you want to understand how the JVM garbage collection process works: