EXAM: Java Basics

Getting Started

• Fork this repository under your own account
• Clone the forked repository to your computer
• Commit your progress frequently and with descriptive commit messages
• All your answers and solutions should go in this repository

What can I use?

• You can use any resource online, but please work individually
• Instead of copy-pasting your answers and solutions, write them in your own words.

Tasks

1. Setup a new project (~5 mins) [5p]

• Create a new project inside your cloned repository
• Setup .gitignore file to exclude the IDE's generated files
  • Just the src directory should be committed
• Create a package called com.greenfox.exams.java and work under that

2. The BlackJack Application (~90 mins) [15p]

The task is to create a BlackJack application where a user Player can play BlackJack with the house Player. The game should have a very simple graphical user interface with two labels (one for the user and one for the house) and two buttons for draw and for resetting the game.

When a new game started a new Deck should be generated with 52 randomly ordered Cards in it. When the user hits the drawCard button the top card of the deck should be added to the users played cards. If the house's played cards sum is under 17 it will draw automatically. After drawing the labels should be updated.

One card drawn:

Two cards drawn:

Layout is not important just put everything in one JPanel with the default layout (no need to change that)

When the user hits the reset button, a new Deck should be generated and players should be reset as well.

Information on the elements

• Tests will be run on your code
  • use names in the code whats used in the description
  • don't use visibility on fields
  • don't use accent in strings or in comments
  • otherwise tests will fail probably
• The BlackJack
  • should be a JPanel
  • should have two buttons, a user and a house Players and a deck
  • should handle the button actions in one method
• The Deck
  • should contain two lists: cards and used, all cards should be in the cards list and after used it should go in to the used list.
  • you can use the Collection.shuffle(list) for shuffling the deck
  • if all cards are used null should be returned when drawing from the deck
• The Card
  • should have a color and a value    - should have a getter for the value    - should be displayed as "color value" eg. "karo 7"
• The Player
  • should have a name
  • should have a list where it stores its played cards
  • should be able to sum the value of its played cards
  • should be able to add a new card to its played cards
  • should be added to the panel and displayed as shown: "Name played: color value..." eg. "User played: kor 7 karo 4 "
• In your main method
  • create a JFrame
  • add BlackJack panel to it
  • make it visible

Acceptance criteria

The application is accepted if:

• All tests pass
• You can check your results here: http://gf-exam.mobil.ninja/
  • In order to register your work you have to create a Pull Request on Github
  • Go to your forked repo (https://github.com/yourname/zerda-java-basics)
  • Click New pull request
  • Then Create pull request
  • After the pull request created your every commit will be evaluated on the site
  • You can check your results

3. Understand the code (~10 mins) [4p]

class Apple {
  public int add(int a, int b) {
    return 5;
  }

  public int max_of_three(int a, int b, int c) {
    if (a > b) {
      return a;
    }
    return c;
  }
}

class TestApple {
  public void testAdd() {
    assertEquals(5, Apple.add(2, 3));
  }

  public void testMax() {
    assertEquals(5, Apple.max_of_three(3, 4, 5));
  }
}

Are the tests passing? Detail your answer! [2p] Fix the situation! [2p]

Explain what you did, and answer the questions here:

First I realised that int the tests the Apple Class' methods are called on the Apple class while the methods are not static. I would add a 'private Apple apple;' field for the TestApple Class, and would add a 'setup()'' method to instantiate the 'apple' Before every test. Then I would call the methods in the tests on this 'apple' like 'apple.add()'. And the annotations '@Test' are missing too from every test case.

4. Question time! (~20 mins) [6p]

Where the abstract class is useful? [2p]

Your answer: When we don't want to create instances of a Class, but we want to use its methods on several extended classes.

Describe a method! Show the necessary parts and how are them called! [2p]

Your answer: A method is a behaviour of a Class like: size() or add(). It can be void or can have a return value, and one can also feed arguments to it inbetween the brackets. Methods can also throw Exceptions if necessary. If static, it can only be called on the Class, otherwise it is called on an instance of a class.

What is the constructor? When it is used? [2p]

Your answer: One can instantiate an instance of a class via calling its constructor. Every Class has an empty constructor, as they are all extended from the Object class. There can be several constructors to a class with different amount of arguments necessary for them.