Throw an exception if age is below 18 (print "Access denied"). If age is 18 or older, print "Access granted":

public class Main {

  static void checkAge(int age) {

    if (age < 18) {

      throw new ArithmeticException("Access denied - You must be at least 18 years old.");


    else {

      System.out.println("Access granted - You are old enough!");




  public static void main(String[] args) {

    checkAge(15); // Set age to 15 (which is below 18...)




Definition and Usage

The throw keyword is used to create a custom error.

The throw statement is used together with an exception type. There are many exception types available in Java: ArithmeticExceptionClassNotFoundExceptionArrayIndexOutOfBoundsExceptionSecurityException, etc.

The exception type is often used together with a custom method, like in the example above.

Differences between throw and throws:



Used to throw an exception for a method

Used to indicate what exception type may be thrown by a method

Cannot throw multiple exceptions

Can declare multiple exceptions


  • throw is followed by an object (new type)
  • used inside the method


  • throws is followed by a class
  • and used with the method signature

Related Pages

Read more about exceptions in our Java Try..Catch Tutorial.