This exercise requires you to handle exceptions. An [exception](https://docs.oracle.com/javase/tutorial/essential/exceptions/definition.html) is an event, which occurs during the execution of a program, that disrupts the normal flow of the program's instructions.

In Java, there are two types of exceptions: checked and unchecked exceptions.

- [Checked vs Unchecked Exceptions in Java](https://www.geeksforgeeks.org/checked-vs-unchecked-exceptions-in-java/)

- [Unchecked Exceptions — The Controversy](https://docs.oracle.com/javase/tutorial/essential/exceptions/runtime.html)

## Checked exceptions

Checked exceptions are the exceptions that are checked at [compile time](https://en.wikipedia.org/wiki/Compile_time).

### Practical implications

You have to declare them in the [method signature](https://docs.oracle.com/javase/tutorial/java/javaOO/methods.html) of any method that can [throw](https://docs.oracle.com/javase/tutorial/essential/exceptions/throwing.html) a checked exception and handle or rethrow them when calling any method that can throw a checked exception.

This is because checked exceptions are meant to be handled at runtime, i.e. they are errors you can recover from.

### Examples of where they are used

They're often used when a method can't return any valid result, for example a search method which hasn't found the item it was searching for.

It's an alternative to returning null or a error code. A checked exception is better than those alternatives because it forces the user of the method to consider the error case.

## Unchecked exceptions

Unchecked exceptions are the exceptions that are not checked at [compile time](https://en.wikipedia.org/wiki/Compile_time).

### Practical implications

You don't have to declare them in the [method signature](https://docs.oracle.com/javase/tutorial/java/javaOO/methods.html) of methods that can [throw](https://docs.oracle.com/javase/tutorial/essential/exceptions/throwing.html) an unchecked exception and handle or rethrow them when calling any method that can throw an unchecked exception.

### Examples of where they are used

Unchecked exceptions are mean to be used for any error than can't be handled at runtime, e.g. running out of memory.