BlueJ provides a different level of interactions with the user than any typical Java environment. Every program execution is just an interactive invocation of a method defined in one of the user-defined classes by an instance of an object created in the Object Viewer.

To support this type of user interactions the tester package provides a static method

public static void run(Object obj);

that determines the class in which the obj has been instantiated, pretty-prints all its fields, and invokes all test methods defined within this class.

• Download the BlueJ from the XXX website and follow the instructions to install the software

• Save the ProfessorJ program you want to run in BlueJ, say in the directory .../ProfJPrograms. Assume the file name is books-authors.java

• Create a directory where you will keep the BlueJ projects, say .../BlueJ

• Create a subdirectory .../BlueJ/Libraries of your .../BlueJ directory where you will keep any library files your project may need

• Download the file tester.jar into the .../BlueJ/Libraries directory

• Download the file ConvertBJ.zip into the .../BlueJ directory and unzip it there

• Start the BlueJ application

• In the Project menu select Open Project then select the ConvertBJ project.

• Now get ready for the first BlueJ project you will run. In the Project menu select Open Project then select the MyProjectBJ project.

• In the Options menu select Preferences and in the Editor section select Display line numbers. This way you can easily find the line for which an error is reported.

• Now choose the Libraries section of the BlueJ: Preferences window and select Add.

• In the file chooser dialog find the file .../BlueJ/Libraries/tester.jar then hit OK in the BlueJ: Preferences window

• Right click on the ConverterBJ box in the main window and select void main(String[])

• In the BlueJ: Method Call dialog that opens up select OK

• You will see a file dialog opened three times. The first time it asks you to choose the ProfessorJ file to be converted. Choose the books-authors.java in the .../ProfJPrograms directory

• The second file dialog asks for the name of the file (and a correct directory) where to save the class definitions part of your program. Select .../BlueJ/MyProjectBJ/books-authors-bj.java

• The third file dialog asks for the name of the file (and a correct directory) where to save the Examples class for your program. Select .../BlueJ/MyProjectBJ/examples-books-authors.java

• You are now ready to run your project in BlueJ. Select the window for the MyProjectBJ

• In the Edit directory select Add Class From File ... then select the book-authors-bj.java file.

• In the Edit directory select Add Class From File ... then select the examples-book-authors-bj.java file.

• Your program is almost ready to run. Double click on the box books-authors-bj.java and edit it by adding the necessary visibility modifiers to the method definitions for methods required when the class implements an interface. By definition all methods defined in an interface are considered to have public visibility and all implementing methods have to match this. Add the word public before the header of every method that is required to implement an interface.

• Click on the Compile button on the top left and make sure the message on the bottom indicates Class compiled - no syntax errors

• Right click on the box examples-book-authors-bj.java and select Compile. You should again get a message Class compiled - no syntax errors

• Right click on the box that now should be labeled Examples ( or whatever the name of your Examples class is) and select new Examples()

• Select the name of this instance - accept the suggestion examples1. A red bow will appear in the bottom left frame

• Right click on this red box and select void run(). The printout of all fields defined in the Examples class as well as the test results will be displayed in the BlueJ: Terminal Window - MyProjectBJ window