In the shared-address-space model there is a common address space shared between
processes and represented as data structures in memory (like ConcurrentHashMap). This gives the advantage of very fast data sharing as shared objects are located on a single computer (let us suppose so for simplicity). As processes may collide, various lock mechanisms (mutex) are helpful to ensure mutual exclusion in accessing shared memory.
This scheme lacks of scalability as an increase in processor number can raise geometrically the traffic on shared memory and a single computer can not have more than say 8 processors.
In the message-passing model there is no sense of global address space. Each process has its one private local memory. Processes can communicate with each other via passing messages. Unlike shared-address-space, the message- passing model offers scalability between processors and memory, although requires the common data to be replicated. An increase in processors will proportionally increase the memory (for that data) size as well, though no lock mechanisms are required in this case.
Reading "Thinking in Java" for inspiration I find only a talk about the shared-address-space model with synchronization principles. As my problem grows in complexity I'm going to try the message-passing paradigm, which as far as I'm not blind, is not presented in the book.
Could you please recommend Java native classes or any proved external library to work with the message-passing model, something like MPI in C++? Any link to that source would be highly appreciated!