mmap'd memory model visibility/synchronization in java

Question

What differences are there (if any) between the regular java memory model for memory in the heap vs an mmap'd file accessed through a direct byte buffer?

Eg if I have multiple threads writing to the byte buffer, is there any special synchronization necessary to ensure that a reader thread will see all the changes?

Answer 1

No difference. Yes, you have to have store synchronized-with edges between writers and the reader to ensure data is written to the buffer.