NullPointerException when subprocess starts or ends --------------------------------------------------- Key: JBPM-455 URL: https://jira.jboss.org/jira/browse/JBPM-455 Project: JBoss jBPM Issue Type: Bug Components: Core Engine Reporter: Eduardo Jimenez Assignee: Tom Baeyens Imagine a scenario where process A calls process B. Process A provides "in" parameters for process B through "read" access variables, and "out" parameters through "write" access variables. Now imagine one of the "out" parameters is optional, say a failure code for instance (say documentation submitted with an application was imcomplete, the code indicates what part of the application was unacceptable). It might be set by process B or it might not be set. When jBPM notifies process A that process B is done, it tries to copy the "out" variable value from process B to process A. If the variable was never set in process B, hence its value is NULL, jBPM throws a RuntimeException because the variable cannot be created in process A with a null value. The same thing happens if an "in" parameter ("read" access variable) is passed to a subprocess and the variable has not been set. In either case, an exception should not be thrown, the variable should just not be created on the subprocess for in variables, or copied to the parent process for out variables.