For BlueJ users: how to make packages; how to use javadoc and jar

I. Constructing packages within BlueJ

Downloads

First, please ensure that you are using BlueJ Version 1.1.4 or newer. This also requires that you install the ``Java 2 Standard Edition,'' JDK 1.3 or newer, also. See http://www.bluej.org/download/download.html to download BlueJ, and see http://java.sun.com/j2se to download the JDK.

Constructing Packages

Say that you want to use BlueJ to construct a folder, Assign1, that contains a package named P. Within package P you wish to insert a class, C.java. Here is what you do:

1. Click on the Project menu, and click on its New Project menu item. A file dialog appears that asks you the name of the folder you wish to create---type Assign1 and press the create button.

   Important: You can tell BlueJ where on your disk you wish to create the folder, Assign1. Remember where you created it --- this will make your life easier when it is time to submit your work for grading.

2. As a result of the previous step, BlueJ creates a new folder named Assign1, and it opens a new window presenting the folder to you. (Alas, in BlueJ, a folder (directory) is called a ``project''!)

   Now, we are ready to create the package, P: Within the Assign1 window, click on the Edit menu, and click on its New Package menu item. A dialog appears and asks you for the name of the package---type P and press OK.

3. As a result of the previous step, a folder named P has been created inside folder Assign1.
4. Now you are ready to include class C within package P. You can do this two ways:

   1. Write it from scratch:

   • double-click on folder P; this opens it and displays a new window.
   • within the window for P, click on the New Class button. A dialog appears and asks for the name of the class---type C and press OK.
   • The previous step creates a file, C.java, inside folder P. When you open C.java, you will find that BlueJ has constructed an empty class that looks like this:

     package P;
     public class C
     { ... }
     

   At this point, you can edit and compile the various java-files as usual.

   2. Copy it from somewhere else:

   Say that class C is already written and saved as the file, C.java, in another folder. You can copy it into the package by

   • double-click on folder P; this opens the package and displays a new window.
   • click on the Edit menu and then click on the Add Class from File menu item.
   • A file dialog appears; use this to locate C.java; once you have located it, press the Add button.

   Note: Unfortunately, I cannot locate a simple shortcut that will let you copy an entire folder of files into a BlueJ-created package. For now, you are stuck copying classes one at a time. (With a bit of effort, you can find a hack.)

II. Using javadoc and jar

Important: There is no guarantee that BlueJ's implementation of javadoc works correctly. If you receive an error message from BlueJ, then you must generate your documentation by starting javadoc from the command window --- see below.

We use the jar program to prepare a CIS300 assignment for submission. At the time of writing, I do not know where to locate jar within BlueJ. Fortunately, a separate copy of jar is included with every installed copy of Java---see below for instructions.

How to use javadoc from the command window:

To use javadoc, try the following:

1. Open a command window (a ``DOS window'').
2. Do cd to the directory where Assign1 lives.
3. Do cd Assign1
4. To generate the API web-pages for all the classes in package P, type javadoc -classpath . P

How to use jar from the command window:

To use jar, try the following:

1. Open a command window (a ``DOS window'').
2. Do cd to the directory where Assign1 lives.
3. Type jar c Assign1 > Assign1.jar

What if javadoc and jar don't work?

• On your C:\ disk drive, locate the folder where java lives; this should be C:\jdk1.3.1_02 or something quite similar.
• Within the jdk1.3.1_02 folder, check that there is a folder named bin, and within bin, there are the programs, javac.exe, java.exe, javadoc.exe, and jar.exe. (There are others in this folder, too.)
• Write down the complete path to the programs. Here it would be, C:\jdk1.3.1_02\bin

Now, we wish to add the directory path, C:\jdk1.3.1_02\bin, to the end of the OS's ``path'' variable.

• To do this, use your OS's ``Help'' manual (look in the ``Start'' menu for it), and check the manual's index for ``path''. You will find one or more entries related to ``path'', ``path command,'' etc. Read them all. At least one of them will indicate how to add C:\jdk1.3.1_02\bin to the end of the path variable. So, do this. Now, reboot.
• To check if you are successful at augmenting the path, reboot, open an MS-DOS window, and type path in it. You will see the value of the path variable. It should look something like this:

  PATH=C:\WINNT\system32;C:\WINNT;C:\jdk1.3.1_02\bin
  

  (This value is a listing of directory paths where executable programs live; you have just added the Java executables to this list.)

What if I cannot reset the path variable?

C:\jdk1.3.1_02\bin\jar c Assign1 > Assign1.jar