However, while the static member variables are in a frame that is allocated in the permgen heap, the objects/arrays referred to by those variables may be allocated in any heap.Ĥ) Objects go on a different heap : Young generation These variables (like all Java variables) will hold either primitive values or object references. I'm guessing that 'internal objects used by JVM (like java/lang/Object)' means JVM-internal class descriptors.ģ) All the static member variables are kept on the Permanent Generation area again. I'm not sure what you mean by some of those things. PermGen no longer exists.Ģ) All the information related to a class like name of the class, Object arrays associated with the class, internal objects used by JVM (like java/lang/Object) and optimization information goes into the Permanent Generation area. Loaded and JIT-compiled classes now go there. including GraalVM.ġ) Classes (loaded by the classloaders) go in a special area on heap : Permanent Generation.Īs of Java 8, the PermGen space has been replaced with Metaspace. The answers below apply to Oracle Hotspot and OpenJDK releases, and probably to most others as well. AFAIK, all current (non-research) 3rd-party JVM implementations are either direct ports of an OpenJDK release or descended from another Sun/Oracle release. The question was therefore Oracle specific. Asking questions on SO, or trawling through random web articles is not a sound academic research technique.Īt the time this question was asked, Sun Microsystems had ceased to exist. and do your own research by reading and understanding the source code. If you want definitive confirmation of your answers, you really need to download the OpenJDK sourcecode. Often it is simplified, inaccurate or just plain wrong. Usually what is written here, or in various articles and web pages, is based on other sources which may or may not be definitive. Most people here (myself included) are answering based on things they have seen written elsewhere, or what they have inferred. Very few people have worked on recent HotSpot JVMs or studied them to the depth needed to really know. Static allocation in java - heap, stack and permanent generationįirst, as should be clear to you by now that there are very few people who can confirm these answers from first hand knowledge.

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