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<a href="https://community.jboss.org/index.jspa" style="text-decoration: none; color: #E1E1E1">JBoss Community</a></h1>
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Re: getProcess in ProcessInstanceImpl throws a NullPointerException
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created by <a href="https://community.jboss.org/people/marco.rietveld">Marco Rietveld</a> in <i>jBPM</i> - <a href="https://community.jboss.org/message/806645#806645">View the full discussion</a>
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<div class="jive-rendered-content"><p>Having written what I've written above (about <em>not fooling around with tx's and the engine</em>), if you are <span style="text-decoration: underline;">really, really, really, really, really, really</span> sure that you want to go down that road, you can do the following: </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Start and  end the JTA transaction yourself. </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>It's that simple: the core persistence mechanism in Drools/jBPM checks to see if there's an active transaction first before starting one -- and it also keeps track of whether or not it started a transaction. That way, it will  <span style="text-decoration: underline;">not</span> commit the transaction if it <span style="text-decoration: underline;">has also not started </span>the transaction. </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>However, as Elmer Fudd used to say, <em>be vewy, vewy </em>careful when you're doing this. Open the tx, do your thing with the engine and close the tx immediately: <em>remember that the process instance state is saved <strong>only</strong> when the transaction commits<strong>. </strong></em>If you do 2 or more actions that modify the process instance, you'll <em>probably</em> be okay. If you modify the processs instance state <em>and</em> "reach into the engine" to do weird things, good luck! </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>Some of the other core committers to the jBPM project would disagree with me about this: they might say "Ahh, Marco's being a wimp -- there are no problems with tx's. Go ahead and have a transaction party!". They will be right 99% of the time -- but if you get into complicated (high load/performance) situations with jBPM and user-controlled tx's, I'd wouldn't bet on it. </p></div>
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