Please write in Java Code:

Prompt

For Project One, which is due in Module Six, you are asked to develop a mobile application for a customer. The customer will provide you with the requirements. Your job is to code the application and provide unit tests to verify that the application meets the customer$$s requirements. For this milestone, you will focus on delivering the contact services. The purpose of these services is to add, update, and delete contact objects within the application.

The contact service uses in$-$memory data structures to support storing contacts $($no database required$).$ In addition, there is no user interface for this milestone. You will verify the contact service through JUnit tests. The contact service contains a contact object along with the contact service. The requirements are outlined below.

Contact Class Requirements

The contact object shall have a required unique contact ID string that cannot be longer than $10$ characters. The contact ID shall not be null and shall not be updatable.

The contact object shall have a required firstName String field that cannot be longer than $10$ characters. The firstName field shall not be null.

The contact object shall have a required lastName String field that cannot be longer than $10$ characters. The lastName field shall not be null.

The contact object shall have a required phone String field that must be exactly $10$ digits. The phone field shall not be null.

The contact object shall have a required address field that must be no longer than $30$ characters. The address field shall not be null.

Contact Service Requirements

The contact service shall be able to add contacts with a unique ID$.$

The contact service shall be able to delete contacts per contact ID$.$

The contact service shall be able to update contact fields per contact ID$.$ The following fields are updatable:

firstName

lastName

Number

Address