Why user defined exceptions in java

But as I explained earlier, you should also provide a constructor method that sets the causing exception and provide a benefit compared to the available standard exceptions. The following example does all of that. As you can see, I added a Javadoc comment that describes the exception. I also implemented a constructor method that sets the causing exception on the superclass. And to provide a benefit compared to the standard exceptions, MyBusinessException uses a custom enumeration to store an error code that identifies the problem.

Clients can use the error code to show localized error messages or tell the user to include this code in a support ticket. You can now throw the MyBusinessException in your code, specify it as part of your method signature and handle it in a catch clause. The implementation of a custom unchecked exception is almost identical to a checked exception.

You should follow the same recommendations as I explained at the beginning of this post. The only difference is that an unchecked exception has to extend RuntimeException instead of Exception. You can use the MyUncheckedBusinessException in the same way as any other unchecked exception. You can throw it in your code and catch it in a catch clause. As described in this post, the implementation of a custom exception is easy. In addition to that, you should follow a few best practices. They make your code easier to read and your API easier to use.

Here are the 4 most important best practices for custom exceptions in Java:. When using Retrace APM with code profiling, you can collect exceptions directly from Java, without any code changes! Click here to read more about the acquisition. By creating your own exception you can make it easier to understand why the exception is thrown and it will stand out better than if you were using an existing exception.

Having said that, in general you should prefer to use the built in Exceptions or at least have your custom Exceptions extend the built-ins so users don't have to care about your special classes unless they want to.

For more info about why you should prefer the built-in exceptions see Effective Java Item Favor the use of standard exceptions. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Ask Question. Asked 7 years, 3 months ago. Active 7 years, 3 months ago. Viewed 3k times. Any elaborate example will be good. Improve this question. David Conrad Almost all general exceptions in Java are provided that happen in Java programming.

We have seen the creation of user-defined exception classes and seen few examples of user-defined exceptions. User need not implement anything inside the class; no methods are required, and also override the toString function to display customized messages. This is a guide to Java User-Defined Exception. You may also have a look at the following articles to learn more —. Submit Next Question. By signing up, you agree to our Terms of Use and Privacy Policy.

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