Can multiple threads see writes on a direct mapped ByteBuffer in Java?

Question

I\'m working on something that uses ByteBuffers built from memory-mapped files (via FileChannel.map()) as well as in-memory direct ByteBuffers. I am trying to understand th

Answer 1

I do not think that this is guaranteed. If the Java Memory Model doesn't say that it's guaranteed it is by definition not guaranteed. I would either guard buffer writes with synchronized or queue writes for one thread that handles all writes. The latter plays nicely with multicore caching (better to have 1 writer for each RAM location).