In most cases, there's no need to define custom exceptions. In our main method, we'll create a new instance of our Foo class, then call the getBar method with the value of zero, which makes that method throw our custom Java exception: The Java Programming Language provides the try, catch, finally, throws and throws keywords to work with exceptions. By the help of custom exception, you can have your own exception and message. Before going to read this tutorial learn when to use checked vs unchecked exceptions in Java. However, if you want to any additional information then you should catch the exception and wrap it in a custom exception. In this article, we'll cover the process of creating custom both checked and unchecked exceptions in Java. Java Custom Exception. And the stack trace tells you in which class, method, and line the exception was thrown. Following these best practices in your Java code will help you in writing robust code. 1. This post is another addition in best practices series available in this blog. It is always best practice to throw the exception back to outer layer or handle the exception and perform some alternative solution. How to find the number of days in a month of a particular year in Java? As explained in best practice #5, the exception message should describe the exceptional event. We should catch exception only when we can handle it appropriately. To achieve that, you must have a good knowledge on best practices used for exception. If you need to add additional information, you should catch the exception and wrap it in a custom one. They make your code easier to read and your API easier to use. How to find the unicode category for a given character in Java? In addition to that, you should follow a few best practices. In my previous tutorial about Java exceptions, I have covered suppressed exceptions and java exception handling. 1.1 If the client is able to recover from the exception, make it a checked exception. Ask Question Asked 4 years, 3 months ago. Exception Handling in Java – Creating Custom Exception Classes. If you'd like to read more about exceptions and exception handling in Java, we've covered it in detail in - Exception Handling in Java: A Complete Guide with Best and Worst Practices Why Use Custom Exceptions? Let's see a simple example of java custom exception. This article lays down some of the best practices which you can use during your design or code reviews. Java Exception handling best practices. 1.1 If the client is able to recover from the exception, make it a checked exception. How to convert a String to an InputStream object in Java? We have been using handling java custom exceptions in our code for almost every industry standard application. A custom exception gives you more control to provide extra data about the problem and to handle the exception in your code. In the above example, whatever exception thrown will be ignored completely and there is no clue on where is the problem. Types of Exception – the exception can be either a checked exception or an unchecked exception. If you are creating your own Exception that is known as custom exception or user-defined exception. Overview Handling Exceptions in Java is one of the most basic and fundamental things a developer should know by heart.