A simple program to manage contacts. Users can add, edit, and remove contacts. The program includes constraints for adding contacts and is implemented in Java with a Java Swing GUI. Contacts are stored in a text file for persistence.

1. Add new contacts with name, phone number, and email address.
2. View a list of all stored contacts sorted alphabetically.
3. Edit existing contact information.
4. Delete unwanted contacts.
5. Store contacts in a text file for persistence.

1. The phone number must be between 8 and 25 digits.
2. The email must contain the '@' symbol.
3. Contacts are sorted and identified by name.
4. No two or more contacts can have the same name.

Java Runtime Environment (JRE) 1.8 or later

1. Download the Contacts Manager.jar file.
2. Click the '+' button to open another window that accepts contact's name, phone, and email. Then, click Save.
3. Select a contact and click the 'Del' button to delete it.
4. Double-click on a field in the contact table to edit it. Then, press Enter to save the changes.