output: #fixed code
                                  public boolean isIterableMapping() {
          return getSingleSourceParameter().getType().isIterableType() && getResultType().isIterableType();
      }
input: #vulnerable code 
                                  public boolean isIterableMapping() {
          return getSingleSourceType().isIterableType() && resultType.isIterableType();
      } 
                              #location 2 
                              #vulnerability type NULL_DEREFERENCE