output: #fixed code
                                @SuppressWarnings({"unchecked", "rawtypes"})
    public void onReceive(ServiceContext serviceContext) throws Throwable {
      FlowMessage fm = serviceContext.getFlowMessage();
      if (serviceContext.isSync() && !syncActors.containsKey(serviceContext.getId())) {
        syncActors.putIfAbsent(serviceContext.getId(), getSender());
      }
  
      // TODO 没有必要设置默认值,下面执行异常就会抛出异常
      Object result = null;// DefaultMessage.getMessage();// set default
      try {
        this.service = ServiceFactory.getService(serviceName);
        result = ((Service) service).process(fm.getMessage(), serviceContext);
      } catch (Throwable e) {
        Web web = serviceContext.getWeb();
        if (web != null) {
          web.complete();
        }
        throw new FlowerException("fail to invoke service " + serviceName + " : " + service + ", param : " + fm.getMessage(), e);
      }
  
      logger.info("同步处理 ： {}, hasChild : {}", serviceContext.isSync(), hasChildActor());
      if (serviceContext.isSync() && !hasChildActor()) {
        logger.info("返回响应 {}", result);
        ActorRef actor = syncActors.get(serviceContext.getId());
        if(actor !=null) {
          actor.tell(result, getSelf());
          syncActors.remove(serviceContext.getId());
        }
        return;
      }
  
      Web web = serviceContext.getWeb();
      if (service instanceof Complete) {
        // FlowContext.removeServiceContext(fm.getTransactionId());
      }
      if (web != null) {
        if (service instanceof Flush) {
          web.flush();
        }
        if (service instanceof HttpComplete || service instanceof Complete) {
          web.complete();
        }
      }
  
      if (result == null)// for joint service
        return;
      if (hasChildActor()) {
        for (RefType refType : nextServiceActors) {
          ServiceContext context = serviceContext.newInstance();
          context.getFlowMessage().setMessage(result);
          // if (refType.isJoint()) {
          // FlowMessage flowMessage1 = CloneUtil.clone(fm);
          // flowMessage1.setMessage(result);
          // context.setFlowMessage(flowMessage1);
          // }
          // condition fork for one-service to multi-service
          if (refType.getMessageType().isInstance(result)) {
            if (!(result instanceof Condition) || !(((Condition) result).getCondition() instanceof String)
                || stringInStrings(refType.getServiceName(), ((Condition) result).getCondition().toString())) {
              refType.getActorRef().tell(context, getSelf());
            }
          }
        }
      } else {
  
      }
    }
input: #vulnerable code 
                                @SuppressWarnings({"unchecked", "rawtypes"})
    public void onReceive(ServiceContext serviceContext) throws Throwable {
      FlowMessage fm = serviceContext.getFlowMessage();
      if (serviceContext.isSync() && !syncActors.containsKey(serviceContext.getId())) {
        syncActors.putIfAbsent(serviceContext.getId(), getSender());
      }
  
      // TODO 没有必要设置默认值,下面执行异常就会抛出异常
      Object result = null;// DefaultMessage.getMessage();// set default
      try {
        this.service = ServiceFactory.getService(serviceName);
        result = ((Service) service).process(fm.getMessage(), serviceContext);
      } catch (Throwable e) {
        Web web = serviceContext.getWeb();
        if (web != null) {
          web.complete();
        }
        throw new FlowerException("fail to invoke service " + serviceName + " : " + service + ", param : " + fm.getMessage(), e);
      }
  
      if (serviceContext.isSync() && !hasChildActor()) {
        syncActors.get(serviceContext.getId()).tell(result, getSelf());
        syncActors.remove(serviceContext.getId());
        return;
      }
  
      Web web = serviceContext.getWeb();
      if (service instanceof Complete) {
        // FlowContext.removeServiceContext(fm.getTransactionId());
      }
      if (web != null) {
        if (service instanceof Flush) {
          web.flush();
        }
        if (service instanceof HttpComplete || service instanceof Complete) {
          web.complete();
        }
      }
  
      if (result == null)// for joint service
        return;
      if (hasChildActor()) {
        for (RefType refType : nextServiceActors) {
          ServiceContext context = serviceContext.newInstance();
          context.getFlowMessage().setMessage(result);
          // if (refType.isJoint()) {
          // FlowMessage flowMessage1 = CloneUtil.clone(fm);
          // flowMessage1.setMessage(result);
          // context.setFlowMessage(flowMessage1);
          // }
          // condition fork for one-service to multi-service
          if (refType.getMessageType().isInstance(result)) {
            if (!(result instanceof Condition) || !(((Condition) result).getCondition() instanceof String)
                || stringInStrings(refType.getServiceName(), ((Condition) result).getCondition().toString())) {
              refType.getActorRef().tell(context, getSelf());
            }
          }
        }
      } else {
  
      }
    } 
                              #location 45 
                              #vulnerability type NULL_DEREFERENCE