Program: 74022
Project: 74022
Buggy source:
/** 
 * Save the model here if there is a new model to apply. and then call super.fire().
 * @exception IllegalActionException If there is no director, or ifthe director's fire() method throws it, or if the actor is not opaque.
 */
public void fire() throws IllegalActionException {
  if (_debugging) {
    _debug("String_Node_Str");
  }
  if (modelString.getWidth() < 1) {
    throw new IllegalActionException(getName() + "String_Node_Str" + "String_Node_Str");
  }
 else   if (modelString.hasToken(0)) {
    StringToken str=null;
    try {
      str=(StringToken)modelString.get(0);
      _parser.reset();
      CompositeActor model=(CompositeActor)_parser.parse(str.stringValue());
      StringWriter writer=new StringWriter();
      try {
        model.exportMoML(writer,1);
      }
 catch (      Exception ex) {
      }
      String modelMoML=writer.toString();
      if (((BooleanToken)connectPorts.getToken()).booleanValue()) {
        _moml="String_Node_Str" + modelMoML + "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ model.getName()+ "String_Node_Str"+ "String_Node_Str"+ model.getName()+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str";
      }
 else {
        _moml="String_Node_Str" + modelMoML + "String_Node_Str";
      }
    }
 catch (    Exception ex) {
      if (_debugging) {
        _debug("String_Node_Str" + str.stringValue());
      }
      throw new IllegalActionException(this,ex,"String_Node_Str" + str.stringValue());
    }
  }
  super.fire();
}

Fixed version (ground truth):
/** 
 * Save the model here if there is a new model to apply. and then call super.fire().
 * @exception IllegalActionException If there is no director, or ifthe director's fire() method throws it, or if the actor is not opaque.
 */
public void fire() throws IllegalActionException {
  if (_debugging) {
    _debug("String_Node_Str");
  }
  if (modelString.getWidth() < 1) {
    throw new IllegalActionException(getName() + "String_Node_Str" + "String_Node_Str");
  }
 else   if (modelString.hasToken(0)) {
    StringToken str=null;
    try {
      str=(StringToken)modelString.get(0);
      _parser.reset();
      CompositeActor model=(CompositeActor)_parser.parse(str.stringValue());
      StringWriter writer=new StringWriter();
      try {
        model.exportMoML(writer,1);
      }
 catch (      Exception ex) {
        throw new IllegalActionException(this,ex,"String_Node_Str" + model);
      }
      String modelMoML=writer.toString();
      if (((BooleanToken)connectPorts.getToken()).booleanValue()) {
        _moml="String_Node_Str" + modelMoML + "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str"+ model.getName()+ "String_Node_Str"+ "String_Node_Str"+ model.getName()+ "String_Node_Str"+ "String_Node_Str"+ "String_Node_Str";
      }
 else {
        _moml="String_Node_Str" + modelMoML + "String_Node_Str";
      }
    }
 catch (    Exception ex) {
      if (_debugging) {
        _debug("String_Node_Str" + str.stringValue());
      }
      throw new IllegalActionException(this,ex,"String_Node_Str" + str.stringValue());
    }
  }
  super.fire();
}