Compiling and adding a ruleflow via KnowledgeBuilder's add method often returns a simple null-pointer exception when information about the actual node that did not compile is available. While one can make a work-around using:

            try

{                 kbuilder.add(workFlow, workFlowtype);             }

catch(Exception t)

{                 KnowledgeBuilderErrors errors = kbuilder.getErrors();                if (errors.size() > 0)                   for (KnowledgeBuilderError error: errors)                       System.err.println(error);                   }

              }
                  throw new IllegalArgumentException("Could not parse knowledge.");
            }
...
      }

throwing an exception with the actual build problem in the message seems appropriate so that users see an error describing the build problem when using traditional exception handling:

try

{ kbuilder.add(workFlow, workFlowtype); }

catch (Exception t)

{ t.printStackTrace() }