If you omit binding attribute for <sub-process> in <process-state> and deploy the process definition with Eclipse or org.jbpm.ant.DeployProcessToServerTask, resolving sub-process will fail. When you run the parent process with jbpm-console after the deployment, jbpm-console will show – "org.jbpm.JbpmException" was thrown. The message is: can't create a process instance when processDefinition is null –

ProcessUploadServlet calls jbpmConfiguration.createJbpmContext() after parsing and before deploying. If jbpmContext is not created before parsing, sub-process won't be resoleved(the call to DbSubProcessResolver.findSubProcess returns null.). So the default behaviour of binding attribute(parse time resolving) will fail.