output: #fixed code
                                  public boolean isInStruct()
      {
          return currentContainerIndex >= 0 && currentContainer().type == ContainerType.STRUCT;
      }
input: #vulnerable code 
                                  public boolean isInStruct()
      {
          return !containers.isEmpty() && currentContainer().type == ContainerType.STRUCT;
      } 
                              #location 3 
                              #vulnerability type NULL_DEREFERENCE