Check pre conditions for scanner system.in

Code:

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public String userInput() {

    Scanner in = new Scanner(System.in);
    boolean cond = true;
    String result;

    // do while loop ensures the characters entered are in the correct format
    do {

      // set cond to false, if input fails any checks then it will be reset to true
      cond = false;
      // accessing user input
      System.out.println("\nType in the characters: ");
      String str = in.next();

      if (some check fails)
        System.out.println("Try Again");
        cond = true;
      }

      result = str
      in.reset();
    } while (cond);

    in.close();
    return result;
}

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My problem is a null pointer exception because of the in.next() statement, I am unsure how to run a check on input and then if failed, attempt to access the keyboard again without using the same scanner. I have put the scanner initiation/closing within the do while but that changed nothing. The scanner reset wasn't what I was looking for either. I am open to a more appropriate design style if anyone has a recommendation, or just a fix for this one.

Thank You for your help.

Don't close the scanner as it's also closing the underlying streams, i.e. System.in.

Code:

---

Scanner in = new Scanner(System.in);
    boolean cond = true;
    String result;
 
    // do while loop ensures the characters entered are in the correct format
    do {
 
      // set cond to false, if input fails any checks then it will be reset to true
      cond = false;
      // accessing user input
      System.out.println("\nType in the characters: ");
      String str = in.nextLine();
 
      if (some check fails)
        System.out.println("Try Again");
        cond = true;
      }
 
      result = str
    } while (cond);
    return result;

---

PROBLEM SOLVED! Thanks All!

-Austin