Looping try/catch

[Joel Christophel]

When I run the below method and intentionally input a letter when a number is expected, I get a never-ending loop that doesn't prompt for more input. Why?

private static int intInput() //Asks the user for an int and returns the input.
  {
Scanner genericIntScan = new Scanner(System.in);
    boolean itsAnInt = false;
    int genericInt = 0;
    
   while(itsAnInt==false)
   {
    try
      {
      genericInt = genericIntScan.nextInt();
      itsAnInt = true;
      }
    catch(InputMismatchException ime)
      {
      System.out.println("\nYou're supposed to type in a number. Try again.");
      itsAnInt = false;
      }
    }
   return genericInt;
}

[Rene Ott]

Your condition is to loop until itsAnInt ==true, lets start looping.
You enter character and then set itsAnInt =true, but because you entered character you catch exception.

    catch(InputMismatchException ime)  
      {  
      System.out.println("\nYou're supposed to type in a number. Try again.");  
      itsAnInt = false;  
      }  

after you catch exception you set itsAnInt = false. Program's next step is to check while loop's condition, which was continue until itsAnInt ==true, but we had itsAnInt = false.

[Joel Christophel]

Well, I tried removing the last "itsAnInt = false" and it didn't change a thing. I also know that itsAnInt is never made true when a non-numerical character is typed in. Here's the code I used to test that:

  
      try {
      genericInt = genericIntScan.nextInt(); //error happens here
      itsAnInt = true; //this and the following line don't get executed
      System.out.println(itsAnInt); //test line
      }

[Joel Christophel]

I found the answer to my problem elsewhere and felt I should share it here. nextLine() is needed to clear the Scanner. Here's the code:

 while(itsAnInt==false)
   {
    try
      {
      genericInt = genericIntScan.nextInt();
      itsAnInt = true;
      }
    catch(InputMismatchException ime)
      {
      genericIntScan.nextLine();
      System.out.println("\nYou're supposed to type in a number. Try again.");
      }
    }