While performing a unit test, with org.jbpm.document.service.impl.DocumentImpl inside the session, audit StringProcessVariableIndexer performs a DocumentImpl.toString() generating a NPE (only when no modificationDate has been set).

This test comes from
https://github.com/mswiderski/jbpm-examples/blob/master/jbpm-open-cmis/src/test/java/org/jbpm/integration/cmis/OpenCMISVariablesProcessTest.java

//The source code is not checking that lastModified can be null.
DocumentImpl. toString()

{ SimpleDateFormat sdf = new SimpleDateFormat( DOCUMENT_DATE_PATTERN ); return name + PROPERTIES_SEPARATOR + size + PROPERTIES_SEPARATOR + sdf.format( ***lastModified*** ) + PROPERTIES_SEPARATOR + link ; }

Alternative:
DocumentImpl. toString()

{ SimpleDateFormat sdf = new SimpleDateFormat( DOCUMENT_DATE_PATTERN ); return name + PROPERTIES_SEPARATOR + size + PROPERTIES_SEPARATOR + ((lastModified!=null)? sdf.format( lastModified ) : "" ) + PROPERTIES_SEPARATOR + link ; }