#vulnerable code 
                              public void manual(String line, DispatchCallback callback)
      throws IOException {
    InputStream in = SqlLine.class.getResourceAsStream("manual.txt");
    if (in == null) {
      callback.setToFailure();
      sqlLine.error(sqlLine.loc("no-manual"));
      return;
    }

    // Workaround for windows because of
    // https://github.com/jline/jline3/issues/304
    if (System.getProperty("os.name")
        .toLowerCase(Locale.ROOT).contains("windows")) {
      sillyLess(in);
    } else {
      try {
        org.jline.builtins.Commands.less(sqlLine.getLineReader().getTerminal(),
            in, sqlLine.getOutputStream(), sqlLine.getErrorStream(),
            null, new String[]{"-I", "--syntax=none"});
      } catch (Exception e) {
        callback.setToFailure();
        sqlLine.error(e);
        return;
      }
    }

    callback.setToSuccess();
  } 
                            #location 13 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                              public void manual(String line, DispatchCallback callback)
      throws IOException {
    InputStream in = SqlLine.class.getResourceAsStream("manual.txt");
    if (in == null) {
      callback.setToFailure();
      sqlLine.error(sqlLine.loc("no-manual"));
      return;
    }

    if (less(in)) {
      callback.setToSuccess();
    } else {
      callback.setToFailure();
    }
  }