We have a rather simple mechanism to execute timers.
Following is the relevant code:

 private static final String EQL_FIND_TIMER_BY_ID = "select ti "
 + "from org.jbpm.scheduler.exe.Timer as ti "
 + "where ti.id = :timerId";

 @SuppressWarnings("unchecked")
 public void executeTimer(final long timerId) {
 JbpmSession jbpmSession = getJbpmSessionFactory().openJbpmSessionAndBeginTransaction();
 Session hibernateSession = jbpmSession.getSession();
 SchedulerSession schedulerSession = jbpmSession.getSchedulerSession();
 try {
 Query query = hibernateSession.createQuery(EQL_FIND_TIMER_BY_ID);
 Timer timer = (Timer) query.setLong("timerId", timerId).uniqueResult();

 if (timer.isDue()) {
 timer.execute();
 }

 } catch (Exception e) {
 LOG.error("Error executin timer id " + timerId, e);
 } finally {
 jbpmSession.close();
 }
 }

any call to executeTimer with an id of a due timer would generate the following error:

java.lang.NullPointerException
 at org.jbpm.graph.def.GraphElement.getRuntimeActionsForEvent(GraphElement.java:208)
 at org.jbpm.graph.def.GraphElement.fireAndPropagateEvent(GraphElement.java:153)
 at org.jbpm.scheduler.exe.Timer.execute(Timer.java:54)
 at com.cbittech.peglogic.core.engine.JbpmWrapperBean.executeTimer(JbpmWrapperBean.java:256)
 at com.cbittech.peglogic.core.engine.JbpmWrapperTest.testExecuteTimers(JbpmWrapperTest.java:88)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:585)
 at junit.framework.TestCase.runTest(TestCase.java:154)
 at junit.framework.TestCase.runBare(TestCase.java:127)
 at junit.framework.TestResult$1.protect(TestResult.java:106)
 at junit.framework.TestResult.runProtected(TestResult.java:124)
 at junit.framework.TestResult.run(TestResult.java:109)
 at junit.framework.TestCase.run(TestCase.java:118)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:478)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:344)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)

This is due to the fact that in GraphElement.getRuntimeActionsForEvent the executionContext has a null processInstance.

What is wrong?