title: Communication between local JVMs
body: <p><strong>My question:</strong> What approach could/should I take to communicate between two or more JVM instances that are running locally?</p>
  
  <p><strong>Some description of the problem:</strong><br>
  I am developing a system for a project that requires separate JVM instances to isolate certain tasks from each other entirely.</p>
  
  <p>In it's running, the 'parent' JVM will create 'child' JVMs that it will expect to execute and then return results to it (in the format of relatively simple POJO classes, or perhaps structured XML data). These results should not be transferred using the SysErr/SysOut/SysIn pipes as the child may already use these as part of its running.</p>
  
  <p>If a child JVM does not respond with results within a certain time, the parent JVM should be able to signal to the child to cease processing, or to kill the child process. Otherwise, the child JVM should exit normally at the end of completing its task.</p>
  
  <p><strong>Research so far:</strong><br>
  I am aware there are a number of technologies that may be of use e.g....</p>
  
  <ul>
  <li>Using Java's RMI library</li>
  <li>Using sockets to transfer objects</li>
  <li>Using distribution libraries such as Cajo, Hessian</li>
  </ul> 
  
  <p>...but am interested in hearing what approaches others may consider before pursuing one of these options, or any others.</p>
  
  <p>Thanks for any help or advice on this!</p>
  
  <p><strong>Edits:</strong><br>
  <strong>Quantity of data to transfer-</strong> relatively small, it will mostly be just a handful of POJOs containing strings that will represent the result of the child executing. If any solution would be inefficient on larger amounts of information, this is <em>unlikely</em> to be a problem in my system. The amount being transferred should be pretty static and so this does <em>not</em> have to be scalable.  </p>
  
  <p><strong>Latency of transfer-</strong> not a critical concern in this case, although if any 'polling' of results is needed this should be able to be fairly frequent without significant overheads, so I can maintain a responsive GUI on top of this at a later time (e.g. progress bar)</p>