output: #fixed code
                                  @Override
      protected <T> T doGet(Class<T> targetClass, int injectDepth) throws ReflectiveOperationException {
          return doGet(targetClass);
      }
input: #vulnerable code 
                                  @Override
      protected <T> T doGet(Class<T> targetClass, int injectDepth) throws ReflectiveOperationException {
          // Aop.get(obj.getClass()) 可以用 Aop.inject(obj)，所以注掉下一行代码
          // targetClass = (Class<T>)getUsefulClass(targetClass);
  
          targetClass = (Class<T>) getMappingClass(targetClass);
  
          Singleton si = targetClass.getAnnotation(Singleton.class);
          boolean singleton = (si != null ? si.value() : this.singleton);
  
          Object ret;
          if (!singleton) {
              ret = createObject(targetClass);
              doInject(targetClass, ret, injectDepth);
              return (T) ret;
          }
  
          ret = singletonCache.get(targetClass);
          if (ret != null) {
              return (T) ret;
          }
  
          //只有在循环依赖的时候，这个context才会有值
          ret = context.get().get(targetClass);
          if (ret != null) {
              return (T) ret;
          }
  
          synchronized (this) {
              ret = singletonCache.get(targetClass);
              if (ret == null) {
  //              ret = createObject(targetClass);
  //              doInject(targetClass, ret, injectDepth);
  //              singletonCache.put(targetClass, ret);
  
                  ret = createObject(targetClass);
  
                  //保存到本次初始化的上下文
                  context.get().put(targetClass, ret);
  
                  //循环注入
                  doInject(targetClass, ret, injectDepth);
  
                  //保存到缓存、并清除上下文数据
                  singletonCache.put(targetClass, ret);
                  context.get().clear();
                  context.remove();
              }
          }
  
          return (T) ret;
      } 
                              #location 14 
                              #vulnerability type THREAD_SAFETY_VIOLATION