Revision history [back]

The default value of java.lang.NumberFormatException is null.

To incorporate it into an if statement for identification, you can check if a certain string input can be parsed as a number using a try-catch block. If a NumberFormatException is caught, it means that the input cannot be parsed as a number and you can handle the exception accordingly. Here's an example:

String input = "123abc";

try {
  int num = Integer.parseInt(input);
  System.out.println(num);
} catch (NumberFormatException e) {
  System.out.println("Invalid input: " + input);
}

In this example, the input "123abc" cannot be parsed as an integer, so a NumberFormatException is caught and the program outputs "Invalid input: 123abc".