Creating Exceptions

Expected time required: 15 min

The goal of the exercise is to create a custom Exception class, called UserExistsException, and to utilize it in a simple service class method. A User POJO provided for you, with the attributes name, email and phoneNumber. The service class is called UserManager, which has a method createUser(User user) that is not complete. createUser() checks to see if the user exists by calling isEmailInUse(). A unit test exists in UserManagerTest to check the case where an email is already in use, triggering the error handling scenario you are asked to complete using the UserExistsException you will create.

1. Complete the UserExistsException class with the 4 recommended constructors. UserExistsException should be a checked Exception. Set up IntellIJ to generate the serialVersionUID for you automatically.

2. Update the createUser method provided for you in UserManager to throw your freshly-implemented UserExistsExcpetion if isEmailInUse() returns true.

You have completed this pre-work when:

• You have implemented the UserExistsException class with all of its constructors.
• You have updated createUser() in UserManager to throw UserExistsException when a new user's email is already in use.
• All tests are passing for both UserExistsExcpetion and UserManager.
• You have committed and pushed your code.
• You have answered the Canvas quiz with a link to your commit on code browser.

HINT:

How do I get IntelliJ to add the serialVersionUID?

In IntelliJ, go to "IntelliJ IDEA" → "Preferences..." → "Editor" → "Inspections" → "Java" → "Serialization issues" → "Serializable class without 'serialVersionUID'" - select the check box and click 'OK'. This will make IntelliJ tell you when a Serializable class is missing the serialVersionUID field.

To have IntelliJ generate the serialVersionUID for you, return to your exception class. The class name should be underlined. If you hover over it, you should see the option to "Add 'serialVersionUID' field". Select that text or press ⌥⇧↵ to generate the serialVersionUID.