While creating your own exception:

• All exceptions must be a child of Throwable.
• If you want to write a checked exception that is automatically enforced by the Handle or Declare Rule, you need to extend the Exception class.
• You want to write a runtime exception, you need to extend the RuntimeException class.

If you want to explore more, visit our Java edu & tutorials section!

Below are some examples:

Super Mario on Java and LibGDX

Data Structures Implementations in Java