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    <p>Java NIO has support for memory-mapped files. If multiple JVMs memory-map the same file they can use it as shared memory.</p> <p>Here is an example of memory mapping a file.</p> <pre><code>try { int shmSize = 1024; RandomAccessFile file = new RandomAccessFile("shm.raw","rw"); // inialize file size if(file.length() &lt; shmSize) { byte[] tmp = new byte[shmSize]; file.write(tmp); file.seek(0); // seek back to start of file. } // memory-map file. FileChannel ch = file.getChannel(); MappedByteBuffer shm = ch.map(FileChannel.MapMode.READ_WRITE, 0, shmSize); ch.close(); // channel not needed anymore. shm.load(); // force file into physical memory. // now use the ByteBuffer's get/put/position methods to read/write the shared memory } catch(Exception e) { e.printStackTrace(); } </code></pre> <p>On Linux you can create the shm.raw file in /dev/shm/ a memory based filesystem. This will help avoid any disk I/O.</p> <p>For more details read this article <a href="http://www.developer.com/java/other/article.php/10936_1548681_1" rel="noreferrer">Introduction to Memory-Mapped IO in Java</a></p> <p>Also you will still need a way to syncronize read/writes to the shared memory. The sender JVM will need to signal the receiver JVM when a complete message has been written.</p> <p>Using Java NIO's SocketChannel might be better for small messages since the receiver can be notified when a message is received. Shared memory will only really help when sending large messages.</p> <p>For IPC between JVMs on different machines try <a href="http://www.garret.ru/jipc/jipc.html" rel="noreferrer">JIPC</a></p>
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    1. COFor inter-machine I am using JGroups or Sockets from communication and for intra-JVM a Queue works. The hole in my communication component is inter-process on the same machine.
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