Storage heap in JVMs

The runtime JVM storage is managed by a single 64-bit storage heap.

The heap for each JVM is allocated from 64-bit storage in the Language Environment® enclave for the JVM. The size of each heap is determined by options in the JVM profile.

The single storage heap is known as the heap, or sometimes as the garbage-collected heap. Its initial storage allocation is set by the -Xms option in a JVM profile, and its maximum size is set by the -Xmx option.

You can tune the size of a heap to achieve optimum performance for your JVMs. See Tuning JVM server heap and garbage collection.