Exception Handling : Custom Exception

In this tutorial, we will discuss about the Custom Exceptions(user defined exceptions).

Custom Exception : Custom exception is simply a user-defined exception. You have studied about several inbuilt exceptions but sometimes application requires some meaningful exceptions to develop. So, we can create our own exceptions by extending Exception class. These custom exception can be thrown using the keyword 'throw' whenever the corresponding condition occurs.

Example :

class MyException extends Exception {
public MyException(String message) {
super(message);
}
}

class CustomException {
public static void main(String[] args) throws Exception {
for (int i = 1; i < 5; i++) {
System.out.println("i = " + i);
if (i == 3) {
throw new MyException("My Exception occurred");
}
}
}
}

Description : In this example, we have created a class MyException that shows custom exception.We have created a for loop that iterate numbers from 1 to 5, whenever loop points to number 3, the custom exception will be thrown using the 'throw' keyword. You can display any message and any logic to show custom exceptions.

Output :

i = 1
i = 2
i = 3
Exception in thread "main" MyException: My Exception occurred
at CustomException.main(CustomException.java:12)

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