Question

Consider the following code.

while (!(productCode >= MIN_PRODUCT_CODE) || !(productCode <= MAX_PRODUCT_CODE)) {
    System.out.println("!!! Invalid product code");
    System.out.print("Enter product code:");
    productCode = Integer.parseInt(input.nextLine());
}

My question is ... how you keep entering user until is valid?
When I entered any number that is invalid input, works fine. I keep entering input value. However, when I entered A , it terminates the program. How do I keep entering the user even if the inputs are String?

Enter product code: a Exception in thread "main" java.lang.NumberFormatException: For input string: "a" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.lang. Integer.parseInt(Integer.java:580) at java.lang. Integer.parseInt(Integer.java:615) at PostTest.main(PostTest.java:92) Process finished with exit code 1

Answer 1

while (!(productCode >= MIN_PRODUCT_CODE) || !(productCode <= MAX_PRODUCT_CODE)) {
System.out.println("!!! Invalid product code");
System.out.print("Enter product code:");

// we should handle the exception when user enters other than number and re initialize the Scanner again
   try{
       productCode = Integer.parseInt(input.nextLine());
   }catch(Exception e){
       input=new Scanner(System.in);
   }
}

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