Oracle WebLogic Server 11g Administration Handbook

Understanding Memory Management

Java objects live in an area called the heap. The heap is not the same as the memory used by the JVM—in addition to the heap, the server uses memory for Java methods, thread stacks, and JVM internal data structures. This is why the virtual size of the process reported by the operating system is different from the number you get when you ask the JVM how much heap it is using. The JVM creates the heap when it starts up, and the heap size varies while applications are running. Applications written in Java are less prone to memory leaks because they rely on the JVM to manage their memory for them. When Java developers write their programs, they do not explicitly free the memory; instead, they simply stop using it ...