How to validate user input in Java? [duplicate]

I'm trying to get user input and check if it is "1" or "2" and display an error messages if it's not. I keep getting error messages even when the input is correct.

Scanner user_input = new Scanner(System.in);
String choice = "";
// Input Validation
do {
   // Read user choice
   choice = user_input.nextLine();
            
   if (!choice.equals("1") || !choice.equals("2"))
      System.out.println("Invalid input. Give new value");
   }while (!choice.equals("1") || !choice.equals("2"));```

Your condition is incorrect. Use logical AND if need to eliminate both 1 and 2. I think you wanted to achieve this

       do {
            choice = user_input.nextLine();

            if (!choice.equals("1") && !choice.equals("2"))
                System.out.println("Invalid input. Give new value");
        } while (!choice.equals("1") && !choice.equals("2"));

Also to remove redundancy and improve the readability of code consider removing the validation logic to a separate method.

public static void main(String[] args) {
        Scanner user_input = new Scanner(System.in);
        String choice = "";
        
        do {
            choice = user_input.nextLine();

            if (isValid(choice))
                System.out.println("Invalid input. Give new value");
        } while (isValid(choice));

        System.out.println("Your input is valid: " + choice);
    }
    
    private static boolean isValid(String choice) {
        return !choice.equals("1") && !choice.equals("2");
    }