output: #fixed code
                                  @Override
      public List<ReferenceTypeUsage> getAllAncestors() {
          List<ReferenceTypeUsage> ancestors = new LinkedList<>();
          if (getSuperClass(typeSolver) != null) {
              ReferenceTypeUsage superClass = getSuperClass(typeSolver);
              ancestors.add(superClass);
              ancestors.addAll(getSuperClass(typeSolver).getAllAncestors());
          }
          ancestors.addAll(getAllInterfaces(typeSolver).stream().map((i)->new ReferenceTypeUsage(i, typeSolver)).collect(Collectors.<ReferenceTypeUsage>toList()));
          return ancestors;
      }
input: #vulnerable code 
                                  @Override
      public List<ReferenceTypeUsage> getAllAncestors() {
          List<ReferenceTypeUsage> ancestors = new LinkedList<>();
          if (getSuperClass(typeSolver) != null) {
              ancestors.add(new ReferenceTypeUsage(getSuperClass(typeSolver), typeSolver));
              ancestors.addAll(getSuperClass(typeSolver).getAllAncestors());
          }
          ancestors.addAll(getAllInterfaces(typeSolver).stream().map((i)->new ReferenceTypeUsage(i, typeSolver)).collect(Collectors.<ReferenceTypeUsage>toList()));
          return ancestors;
      } 
                              #location 5 
                              #vulnerability type NULL_DEREFERENCE