#vulnerable code 
                              @Override
  public void enterScope(NodeTraversal t) {
    new GraphReachability<Node, ControlFlowGraph.Branch>(
        t.getControlFlowGraph(), new ReachablePredicate()).compute(
            t.getControlFlowGraph().getEntry().getValue());
  } 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              @Override
  public void enterScope(NodeTraversal t) {
    scopeNeedsInit = true;
  }