OOP Lab Task 1

Required Tutorials

• The Object Oriented Paradigm; Classes and Objects
• Notions About the Java Language
• Writing and Executing a Java Program
• Java Syntax; A Program's Lexical Structure
• Java Coding Conventions

Requirements

• Create a Java application project whose name is oop_lab1.
• Add to your project a class Message (that may be used some time in the future as a data carrier between a chat client and all the other clients connected to a server). This class needs to:
  • Store the name of the sender and a message content.
  • Be immutable (once an object of this type is created, its content cannot be changed).
  • Allow reading of the sender and content information from Message objects in a way specific to chat programs: "sender: contents". This must be done using only one method call that returns the formatted string, ready to be displayed by any print method. Try first with a method of your own. Then, add another method, that does exactly the same thing but whose declaration is public String toString().

• Write another class called Main (the default class created if you created a project within NetBeans), which should contain only the main method, that instantiates at three objects of type Message and then displays for each of them their formatted string on the screen using the System.out print method, first with a single String argument, the String returned by your method from Message class, and then with the object's reference as its sole argument.

Notes:

• Each class and class member must have one of the two access modifiers public or private.
• The names of the classes must be identical to the ones specified above.
• Follow the coding rules stated in Java Coding Conventions.

Submitting:

• The assignment will be evaluated automatically by the WebCAT platform.
• You could access the Web-CAT platform using the username and the password with which you acces the studenti.pub.ro intranet.
• If your username and password are valid you should be able to enter your Web-CAT student page (but there is still no course attached to you). If you are unable to acces studenti.pub.ro, contact the UPB net administrator.
• To be enrolled in the OOP lab on the Web-CAT platform you should first add your identification info (intranet username, name, surname, group, e-mail address) into the user registration document. Your registration is checked by the administrator, therefore it may finish after a couple of days.
• Once you are enrolled in the Web-CAT OOP lab, you may submit your work to the active task assignemnts.
• To submit your work you upload a single .zip archive containing only the Java source code files.
• If your work contains a single Java file you may directly upload that single file, unarchived.
• Attention Any deviation from these instructions may lead to the loss of the entire amount of points.