#vulnerable code 
                              private String getFunctionAnnotation(Node fnNode) {
    Preconditions.checkState(fnNode.getType() == Token.FUNCTION);
    StringBuilder sb = new StringBuilder("/**\n");

    JSType type = fnNode.getJSType();

    if (type == null || type.isUnknownType()) {
      return "";
    }

    FunctionType funType = type.toMaybeFunctionType();

    // We need to use the child nodes of the function as the nodes for the
    // parameters of the function type do not have the real parameter names.
    // FUNCTION
    //   NAME
    //   LP
    //     NAME param1
    //     NAME param2
    if (fnNode != null) {
      Node paramNode = NodeUtil.getFunctionParameters(fnNode).getFirstChild();

      // Param types
      for (Node n : funType.getParameters()) {
        // Bail out if the paramNode is not there.
        if (paramNode == null) {
          break;
        }
        sb.append(" * @param {" + getParameterNodeJSDocType(n) + "} ");
        sb.append(paramNode.getString());
        sb.append("\n");
        paramNode = paramNode.getNext();
      }
    }

    // Return type
    JSType retType = funType.getReturnType();
    if (retType != null && !retType.isUnknownType() && !retType.isEmptyType()) {
      sb.append(" * @return {" + retType + "}\n");
    }

    // Constructor/interface
    if (funType.isConstructor() || funType.isInterface()) {

      FunctionType superConstructor = funType.getSuperClassConstructor();

      if (superConstructor != null) {
        ObjectType superInstance =
          funType.getSuperClassConstructor().getInstanceType();
        if (!superInstance.toString().equals("Object")) {
          sb.append(" * @extends {"  + superInstance + "}\n");
        }
      }

      if (funType.isInterface()) {
        for (ObjectType interfaceType : funType.getExtendedInterfaces()) {
          sb.append(" * @extends {" + interfaceType + "}\n");
        }
      }

      // Avoid duplicates, add implemented type to a set first
      Set<String> interfaces = Sets.newTreeSet();
      for (ObjectType interfaze : funType.getImplementedInterfaces()) {
        interfaces.add(interfaze.toString());
      }
      for (String interfaze : interfaces) {
        sb.append(" * @implements {"  + interfaze + "}\n");
      }

      if (funType.isConstructor()) {
        sb.append(" * @constructor\n");
      } else if (funType.isInterface()) {
        sb.append(" * @interface\n");
      }
    }

    if (fnNode != null && fnNode.getBooleanProp(Node.IS_DISPATCHER)) {
      sb.append(" * @javadispatch\n");
    }

    sb.append(" */\n");
    return sb.toString();
  } 
                            #location 24 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              private String getFunctionAnnotation(Node fnNode) {
    Preconditions.checkState(fnNode.getType() == Token.FUNCTION);
    StringBuilder sb = new StringBuilder("/**\n");

    JSType type = fnNode.getJSType();

    if (type == null || type.isUnknownType()) {
      return "";
    }

    FunctionType funType = (FunctionType) fnNode.getJSType();

    // We need to use the child nodes of the function as the nodes for the
    // parameters of the function type do not have the real parameter names.
    // FUNCTION
    //   NAME
    //   LP
    //     NAME param1
    //     NAME param2
    if (fnNode != null) {
      Node paramNode = NodeUtil.getFunctionParameters(fnNode).getFirstChild();

      // Param types
      for (Node n : funType.getParameters()) {
        // Bail out if the paramNode is not there.
        if (paramNode == null) {
          break;
        }
        sb.append(" * @param {" + getParameterNodeJSDocType(n) + "} ");
        sb.append(paramNode.getString());
        sb.append("\n");
        paramNode = paramNode.getNext();
      }
    }

    // Return type
    JSType retType = funType.getReturnType();
    if (retType != null && !retType.isUnknownType() && !retType.isEmptyType()) {
      sb.append(" * @return {" + retType + "}\n");
    }

    // Constructor/interface
    if (funType.isConstructor() || funType.isInterface()) {

      FunctionType superConstructor = funType.getSuperClassConstructor();

      if (superConstructor != null) {
        ObjectType superInstance =
          funType.getSuperClassConstructor().getInstanceType();
        if (!superInstance.toString().equals("Object")) {
          sb.append(" * @extends {"  + superInstance + "}\n");
        }
      }

      if (funType.isInterface()) {
        for (ObjectType interfaceType : funType.getExtendedInterfaces()) {
          sb.append(" * @extends {" + interfaceType + "}\n");
        }
      }

      // Avoid duplicates, add implemented type to a set first
      Set<String> interfaces = Sets.newTreeSet();
      for (ObjectType interfaze : funType.getImplementedInterfaces()) {
        interfaces.add(interfaze.toString());
      }
      for (String interfaze : interfaces) {
        sb.append(" * @implements {"  + interfaze + "}\n");
      }

      if (funType.isConstructor()) {
        sb.append(" * @constructor\n");
      } else if (funType.isInterface()) {
        sb.append(" * @interface\n");
      }
    }

    if (fnNode != null && fnNode.getBooleanProp(Node.IS_DISPATCHER)) {
      sb.append(" * @javadispatch\n");
    }

    sb.append(" */\n");
    return sb.toString();
  }