Learning Objectives:
• Exploring BlueJ IDE with Java SE 8 (JDK)
• Understanding compile-time, link-time, run-time, and logical errors
1. Follow the instructions below very closely, create a small program, compile, and test it.
a. Open the P drive and create a folder named BlueJ, if it does not exist already. Under this folder, create another subfolder named CSC203 for this course, if it does not exist already. I strongly recommend that you keep your computer work for this course properly organized in this folder.
b. Launch BlueJ and create a BlueJ project named LAB02 under the CSC203 folder mentioned in the previous step.
c. Create a class named Roman. Open the editor and delete all the code placed in it automatically by BlueJ. Choose Options and Preferences and then check Display Line Numbers. Also, choose the options Class and Page Setup... and set the Orientation to Landscape. Use a web browser, access the class site on Blackboard, locate the file named Roman.java, open it, copy and then paste it as code for the class Roman. Replace my name with that of yours and change the date suitably. Make sure to delete blank lines on top and bottom. Deleting blank lines on top and bottom is necessary to correctly record the line numbers for errors.
d. Compile the code. You will receive a number of compile-time (syntax) error messages. You are required to read the error messages, think about them and fix them, even though you may not fully understand the entire program code.
e. Download from Blackboard and save the Microsoft Word document named Lab02_Error_Report under P:\BlueJ\CSC203\LAB02. Open the file and record each error, with the class name, the line number, the error message, and what was done to fix the error. When the class successfully compiles, close the editor window.
f. Create a new class named RomanProcessor. Open the editor and delete all the code placed in it automatically by BlueJ. Use a web browser, access the class site on Blackboard, locate the file named RomanProcessor.java, open it, copy and then paste it as code for the class RomanProcessor. Replace my name with that of yours and change the date suitably. Again, make sure to delete blank lines on top and bottom.
g. Compile the RomanProcessor code. If there are errors, edit the code carefully and ensure that it compiles successfully. There should be one. This error is technically a link-time error when Java is looking for an appropriate class to import in the java.util package. Carefully record in the Microsoft Word document the class name, the line number, the error message, and what was done to fix the error.
h. In the project window, move the two classes (rectangular boxes) around a bit to show clearly their relationship. There will be an arrow going from the class RomanProcessor to Roman indicating the class relationship.
i. Note that there is a main method only in RomanProcessor class and it uses the Roman class. Also note that the method title for main in RomanProcessor has the qualifier static in it. Therefore you do not have to create an instance of the class to test the program. Just right clicking the RomanProcessor class diagram will show you the main method that can be selected for execution.
j. Let us first test the program for one test case: XLIX which stands for 49. First, in the terminal window, choose Options and select Unlimited buffering and Clear screen at method call. Try the test case XLIX. You will immediately encounter a run-time error. The editor window will open up, showing a line at which the run-time error was encountered. That should be the line at which you are attempting to assign a value to the variable currentChar. Carefully record, in the Microsoft Word file, the error message seen. Also see the terminal window that will show more detail about the error. Again, carefully record, in the Microsoft Word file, the error message seen.
k. In this case the String roman has only four characters, with their index values running from 0 to 3. Hence an index value of 4 causes an error. The error is fixed by making a change in the previous line: change index <= len to index < len
l. Recompile the code again and run the program for the test case XLIX. It should show the correct result of 49. Run the program for the test case MMXVII. The expected answer is 2017. The program should show a wrong result. Obviously there are logical errors. We need to test the program thoroughly.
m. Below are given a number of Roman numeral strings with their equivalent decimal values. First, in the terminal window, make sure to choose Options and select Unlimited buffering and Clear screen at method call. Try all these test cases, one by one, going row by row. The program has one logical error. Hence it will not produce the correct output for all cases. Carefully record, in the Microsoft Word file, the test cases for which the program produced incorrect results.
I = 1    II = 2       III = 3    IV = 4
V = 5    VI = 6    VII = 7    VIII = 8
IX = 9    X =10       L = 50    C = 100
D = 500 M = 1000    XXXII = 32    XLIX = 49
CXC = 190    MCMLXXXIX = 1989    MCMXCVII = 1997 MMXVII = 2017
n. You have to locate the logical errors and fix them, by suitably editing the class Roman. The test cases for single letter roman numerals should help you identify the errors. Obviously you need to recompile the code every time you change it. Carefully record, in the Microsoft Word file, the changes made to fix the logical errors.

Learning Objectives: • Exploring BlueJ IDE with Java SE 8 (JDK) •...