Program: 167491
Project: 167491
Buggy source:
@Override public void start(String executionId,IExecutionTracker executionTracker){
  super.start(executionId,executionTracker);
  String importStatements=flowStep.getComponent().get(IMPORTS);
  String initScript=flowStep.getComponent().get(INIT_SCRIPT);
  String handleMessageScript=flowStep.getComponent().get(HANDLE_SCRIPT);
  String onSuccess=flowStep.getComponent().get(ON_FLOW_SUCCESS);
  String onError=flowStep.getComponent().get(ON_FLOW_ERROR);
  ScriptEngineManager factory=new ScriptEngineManager();
  ScriptEngine engine=factory.getEngineByName("String_Node_Str");
  engine.put("String_Node_Str",this);
  StringBuilder script=new StringBuilder();
  try {
    script.append(String.format("String_Node_Str",IMessageTarget.class.getName()));
    script.append(String.format("String_Node_Str",Message.class.getPackage().getName()));
    script.append(String.format("String_Node_Str",MessageScriptHelper.class.getName()));
    script.append("String_Node_Str");
    if (isNotBlank(importStatements)) {
      script.append(importStatements);
    }
    script.append("String_Node_Str");
    script.append(String.format("String_Node_Str",MessageScriptHelper.class.getSimpleName()));
    if (isNotBlank(initScript)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",initScript));
    }
    if (isNotBlank(handleMessageScript)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",handleMessageScript));
    }
    if (isNotBlank(onSuccess)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",onSuccess));
    }
    script.append("String_Node_Str");
    if (isNotBlank(onError)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",onError));
    }
    script.append("String_Node_Str");
    executionTracker.log(executionId,LogLevel.DEBUG,this,script.toString());
    script.append("String_Node_Str");
    engine.eval(script.toString());
    this.engine=engine;
  }
 catch (  ScriptException e) {
    Throwable rootCause=ExceptionUtils.getRootCause(e);
    if (rootCause != null) {
      if (rootCause instanceof RuntimeException) {
        throw (RuntimeException)rootCause;
      }
 else {
        throw new RuntimeException(rootCause);
      }
    }
 else {
      throw new RuntimeException(e);
    }
  }
}

Fixed version (ground truth):
@Override public void start(String executionId,IExecutionTracker executionTracker){
  super.start(executionId,executionTracker);
  String importStatements=flowStep.getComponent().get(IMPORTS);
  String initScript=flowStep.getComponent().get(INIT_SCRIPT);
  String handleMessageScript=flowStep.getComponent().get(HANDLE_SCRIPT);
  String onSuccess=flowStep.getComponent().get(ON_FLOW_SUCCESS);
  String onError=flowStep.getComponent().get(ON_FLOW_ERROR);
  ScriptEngineManager factory=new ScriptEngineManager();
  ScriptEngine engine=factory.getEngineByName("String_Node_Str");
  engine.put("String_Node_Str",this);
  StringBuilder script=new StringBuilder();
  try {
    script.append(String.format("String_Node_Str",IMessageTarget.class.getName()));
    script.append(String.format("String_Node_Str",Message.class.getPackage().getName()));
    script.append(String.format("String_Node_Str",MessageScriptHelper.class.getName()));
    script.append("String_Node_Str");
    if (isNotBlank(importStatements)) {
      script.append(importStatements);
    }
    script.append("String_Node_Str");
    script.append(String.format("String_Node_Str",MessageScriptHelper.class.getSimpleName()));
    if (isNotBlank(initScript)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",initScript));
    }
    if (isNotBlank(handleMessageScript)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",handleMessageScript));
    }
    if (isNotBlank(onSuccess)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",onSuccess));
    }
    if (isNotBlank(onError)) {
      script.append("String_Node_Str");
      script.append(String.format("String_Node_Str",onError));
    }
    script.append("String_Node_Str");
    executionTracker.log(executionId,LogLevel.DEBUG,this,script.toString());
    script.append("String_Node_Str");
    engine.eval(script.toString());
    this.engine=engine;
  }
 catch (  ScriptException e) {
    Throwable rootCause=ExceptionUtils.getRootCause(e);
    if (rootCause != null) {
      if (rootCause instanceof RuntimeException) {
        throw (RuntimeException)rootCause;
      }
 else {
        throw new RuntimeException(rootCause);
      }
    }
 else {
      throw new RuntimeException(e);
    }
  }
}