<p>what is the best method for inter process communication in a multithreaded java app.</p>

<p>It should be performant (so no JMS please) easy to implement and reliable,so that
objects &amp; data can be bound to one thread only?</p>

<p>Any ideas welcome!</p>

Could you clarify a bit?  Do you mean IPC in a single JVM? (Multiple threads, yes, but at an OS-level only one process.)  Or do you mean multiple JVMs?  (And truly OS-level inter process communications.)
If it is the first, then maybe something out of
java.util.concurrent
, like
ConcurrentLinkedQueue
would do the trick.  (I pass message around inbetween my threads with classes from java.util.concurrent with success.)
If the later, then I'm going to just guess and suggest taking a look at
RMI
, although I don' think it qualifies as fully reliable--you'd have to manage that a bit more 'hands on' like.