Create Custom Exception Class in Java

Category: Java   Tags: Java, Java Basic, Java Exception Handling, Java Custom Exception

Here I will show you how to create a custom Java exception class. If you want to know more about Java exception, go here Java Exception Handling.

By making a subclass of Exception class you can create a custom exception in Java. Exception class inherit all methods provided by Throwable, therefore all exception class including your custom exception class can use all methods provided by Throwable.

                          package com.tutorial.javabasic;

                          class MyException extends Exception {

                              private String description;
                              public MyException(String str) {
                                  description = str;

                              public String toString() {
                                  return "MyException: " + description;


                          public class JavaCustomExceptionExample {

                              public static void main(String s[]) throws MyException {
                                  int a = 100;
                                  if(a < 1000)
                                      throw new MyException("a is less than 1000");


                          Exception in thread "main" MyException: a is less than 1000
                            at com.tutorial.javabasic.JavaCustomExceptionExample.main(

Overriding toString() allows you to format exception description in your way.