Java Interfaces ... Dynamic or Static Memory?

Question

Where are the java interfaces in memory? Are they on the heap or the stack, or maybe in global memory? I think they are on the stack since they are created at compile time. Am I right?

Answer 1

Class definitions, including interfaces and abstract classes, are stored in the PermGen space, meaning they are never garbage collected. PermGen is, iirc, part of the heap.

Answer 2

Interfaces are not technically “created” in the sense that an instance of a regular class is created, but class information is stored in java space. See http://blogs.oracle.com/jonthecollector/entry/presenting_the_permanent_generation for more information on permgen and the difference between a class instance and class information.

Answer 3

Class definitions (including interfaces, etc.) are stored on the heap (usually in the constant generation, because their lifespan is long). If the ClassLoader they ClassLoader is garbage collection, then they also have the right to garbage collection.