Custom Exceptions
If you want to create your own exceptions then it is called as custom exception or user-defined exception. These are used to customize the exceptions as per user requirements. With these exceptions, we can have our own exception and message.
Syntax:
throw new exception;
Custom exceptions allow you to provide characteristics and methods that aren't included in normal Java exceptions. These can hold additional data, such as an application-specific error code, or provide utility methods for handling or presenting the exception to the user.
The following are the primary motivations for implementing custom exceptions:
- Exceptions about business logic and workflow are known as business logic exceptions. They aid the app users and developers in determining the specific nature of the issue.
- To catch and treat a subset of current Java exceptions in a certain way.
Essential notes about Java Custom Exceptions:
- Exceptions defined by the user must extend the Exception class.
- The throw keyword is used to throw the exception.
- Throwable must be the parent of all exceptions.
- You must extend the Exception class if you want to build a checked exception enforced automatically by the Handle or Declare Rule.
- You must extend the RuntimeException class if you wish to write a runtime exception.
Catch block
Java is a programming language
Example:
<![CDATA[
Com.knowledge2life
class MyCustomException extends Exception
{
}
public class Main
{
public static void main(String args[])
{
try
{
throw new MyCustomException();
}
catch (MyCustomException ex)
{
System.out.println("Caught the exception");
System.out.println(ex.getMessage());
}
System.out.println("rest of the code...");
}
}
]]>
OUTPUT:
Caught the exception
null
rest of the code...
