Currently Java objects have a 128-bit object header in the 64-bit HotSpot VM, with a 64-bit multipurpose header word and a 64-bit class pointer. With average object sizes of five to six words, ...

Major Java enhancement projects for the coming year include work on code reflection, AOT compilation, eight-byte object headers, and finalizing the structured concurrency and scoped values APIs.

Here is a list of restrictions imposed by Java memory model that prevent achieving maximum performance: Each object is allocated on the heap. There is storage overhead for object header and data ...