Creating your own exception
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There are two types of exceptions in Java: built-in exceptions and user-defined exceptions. Built-in exceptions are available in Java libraries and cover common error situations, while user-defined exceptions involve creating a new exception class that extends the Exception class and throwing it with the throw keyword to handle custom error situations in code. The example shows creating an InvalidAgeException class, throwing it from a validate method if age is less than 18, and catching it to print an error message.
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![3/18/2019 Creating your own exception: Your Guided Course Template
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Crea ng your own excep on
Types of Exception in Java
Built-in Exceptions
User-Defined Exceptions
Built-in exceptions:
Built-in exceptions are the exceptions which are available in Java libraries. These exceptions are suitable
to explain certain error situations.
User-Defined Exceptions
User Defined Exception or custom exception is creating your own exception class and throws that
exception using ‘throw’ keyword. This can be done by extending the class Exception.
Example of java custom exception:
class InvalidAgeException extends Exception
{
InvalidAgeException(String s)
{
super(s);
}
}
class TestCustomException1
{
static void validate(int age)throws InvalidAgeException
{
if(age<18)
throw new InvalidAgeException("not valid");
else
System.out.println("welcome to vote");
}
public static void main(String args[])](https://image.slidesharecdn.com/creatingyourownexceptionyourguidedcoursetemplate-190404025502/85/Creating-your-own-exception-1-320.jpg)
Creating your own exception
- 1. 3/18/2019 Creating your own exception: Your Guided Course Template https://canvas.instructure.com/courses/1480238/pages/creating-your-own-exception?module_item_id=21012890 1/2 Crea ng your own excep on Types of Exception in Java Built-in Exceptions User-Defined Exceptions Built-in exceptions: Built-in exceptions are the exceptions which are available in Java libraries. These exceptions are suitable to explain certain error situations. User-Defined Exceptions User Defined Exception or custom exception is creating your own exception class and throws that exception using ‘throw’ keyword. This can be done by extending the class Exception. Example of java custom exception: class InvalidAgeException extends Exception { InvalidAgeException(String s) { super(s); } } class TestCustomException1 { static void validate(int age)throws InvalidAgeException { if(age<18) throw new InvalidAgeException("not valid"); else System.out.println("welcome to vote"); } public static void main(String args[])
- 2. 3/18/2019 Creating your own exception: Your Guided Course Template https://canvas.instructure.com/courses/1480238/pages/creating-your-own-exception?module_item_id=21012890 2/2 { try { validate(13); }catch(Exception m) { System.out.println("Exception occured: "+m); } System.out.println("rest of the code..."); } } Output:Exception occured: InvalidAgeException:not valid rest of the code...