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Developing Java Programs
The situation regarding tools for Java programming is confusing.
First of all you need to get a JDK.
Secondly you need to set some paths on your machine.
Thirdly you need to get some kind of IDE tool for editing and
building your files.
Fourthly, you'll need to frequently check the Java documentation
online, for instance at Paintings & Links JDK 1.3 Documentation
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The JDK
Sun gives away packages
with a command-line compiler and libraries for developing Java
code; these packages are called JDK (for Java Developer's Kit).
The commonly used editions at this time are JDK: 1.1,
1.2.2, 1.3, and now 1.4. JDK 1.2 and higher are referred
to be Sun as " Java 2".
In writing a Java program,
you use a text editor of some kind to make one or more *.java
files. You use a Sun utility known as javac.exe to
compile the *.java files into *.class files. The compiler
will pull in a number of Java library or "package" files
from your disk and link them into your code. And then you
execute the *.class files and see a program running by using either
(i) a Sun "virtual machine" utility known as java.exe
or (ii) a web browser. The Java libraries, javac.exe, and
java.exe all come as part of the JDK.
The various Java JDK (sometimes also called SDK for Software
Devloper's Kit) are downloadable from
the Web at Sun's java.sun.com site. A JDK includes, among
other things, the javac.exe and java.exe utilites as well as some
libraries of *.java code files. Note that it's okay to install
several JDK on your machine, in separate directories.
Another point to mention here is that when you go to the Sun
download page, you have a choice of getting the SDK or the Runtime
Environment. Normally you would want the SDK.
The "SDK "includes all the libraries, the javac.exe
compiler, the java.exe virtual machine, and a plug-in to (maybe)
make the Java files work with your current web browser.
The "Runtime Environment" leaves out the javac.exe
compiler, but includes some of the libraries, the virtual machine,
and the plug-in.
Download a JDK From Sun. This is about
30 Meg, so do it with a fast connection.
There is another thing you
can download, this is the "Documentation". You
definitely would like to get this too To get documentation for
the Java SDK, you can download the documentation, which is in
HTML format and about 20 Meg. Alternately, you can browse
the documentation online at Paintings & Links JDK 1.3 Documentation
or Paintings & Links Java 1.1
Documentation.
By the way, if you can't manage the huge downloads, you can buy
these wares directly from Sun on CD. Also note that some
Sun downloads are only availabe during business hours on weekdays.
The Sun Java SDK does not
come with any type of IDE (integerated developer environment).
For simple programs you do best to use Textpad as described below.
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Setting your Path
In order to run javac, java, and textpad from the DOS command
line your path must include the directories where javac.exe and
java.exe live and the directory where textpad.exe lives. On my
machine these recently happened to be c:\Program Files\j2sdk1.3.1\bin
for the two Java utilities, and c:\Program Files\Textpad 4 for
Textpad.
If you have NT, you set the path by opening Start|Settings|Control
Panel|System|Environment. Click on the Path line, edit it in the
bottom of the dialog, and press Set to record your editing. Separate
all path fields by semi-colons but not with spaces. A good path
to use in the lab might look like this
c:\Program Files\j2sdk1.3.1\bin;c:\Program Files\Textpad 4
If you have Win98, you will have a C:\autoexec.bat file that
you can edit. If you don't find autoexec.bat in the C:\ root,
use Start|Find to find it. Use any text editor to add a line like
this. The final %path% means to keep whatever was in the path
before.
set path=c:\Program Files\j2sdk1.3.1\bin;c:\Program Files\Textpad
4;%path%
On some versions of Win98 (or Win95), a path like
c:\Program Files\Textpad 4
isn't recognized. You can use the DOS versions of the two-word
names instead
c:\Program~1\Textpad~1
You know you have the path
fixed if you can enter java, javac, and textpad at the command
line and get responses other than "...not found."
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An Integrated Development
Environment (IDE)
If you plan to write Java
programs of any size, it would be nice to have an IDE (integrated
development environemnt) that has integrated help, which lets
you build and run from the edit interface, which highlights errors,
and which has some debugging capability. I still haven't
found a Java IDE that I really like.
There are various goals
in choosing your compiler. Unfortunately these goals seem to be
incompatible.
(1) An IDE (Integrated Development Environment) similar to, for
instance Microsoft Visual Studio, that is, a multi-windowed environment
in which we can edit, compile, and run our programs, with ability
to pop up help files and perhaps even do some WYSIWYG (What you
see is what you get) editing of our GUI (Graphical User Interface).
(2) Write Java applets that are useable by a wide range of browsers.
(3) Run in a stable fashion on your machine.
(4) Support the latest features of Java.
(5) Don't have to do huge downloads over the Web.
(6) Pay very little.
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Textpad 4.6
A good low-end Java developement
environment is to install a Sun JDK and use the free TextPad 4.6
editor from www.textpad.com.
This isn't really a full IDE, but it's a lot better than working
at the command line.
Spend some time looking
at the Textpad menus to get it configured properly. To
begin with use View to turn off the Clip Library and Document
Selector windows.
You should install Java
BEFORE you install Textpad, otherwise you won't be able to add
the Java Tools. If Java is already installed, then you can use
Configure|Preferences|Tools|Add to add the JDK commands if they
are not already present under the Tools menu.
If you don't see the Configure|Preferences|Tools
option then you are going have to use the Tools|Run dialog to
compile your java. In the Tools|Run dialog fill in javac as the
comand, and either filename.java or *.java as the Parameters.
You may need to set Initial folder as well. Check DOS Command
and check Capture Output. The Run dialog will keep the same selections
over a session, so it's useful.
Use Configure|Preferences|Document
Classes|Java|Syntax to Enable Syntax Highlighting and select the
java.syn syntax file.
You can use Editor|Keystroke
compatability to select Microsoft Applications to use the familiar
Microsoft shortcuts. You can use Configure|Preferences|Keyboard|Tools
to select shortcut keys Ctrl+1 and Ctrl+2 for JDK Compile and
JDK Run Application. You can shortcut other keys as well. You
can use Configure|Preferences|Document Classes|Default|Font to
select bigger fonts. And so on. Textpad has a good help file.
One new feature in
4.6 is that can create a Textpad "workspace" file which
opens up a whole bunch of *.java files at once. When you call
Tools|Compile, all the open files get compiled.
If there is an error,
you see a window with error messages. Double clicking on an error
message takes you to it.
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Sun ONE (Formerly
known as Forte)
Sun provides a free Java
IDE called ONE (formerly known as Forte), which is a fairly serviceable
IDE for Java development. You can download it (I think only
on weekdays) from Sun's ONE Studio 4.0 For
Java Community Edition Download page. You need
at least 128 Meg of RAM on your computer to run this program.
The earlier version called Forte is on our lab machines. In the
past, I've found Forte too slow and too unergonomic (you can't
use the mouse wheel to scroll and there aren't many hotkey shortcuts,
you have to click a lot, and the dialogs aren't standard Windows
dialogs) to really be useable.
But ONE is said to be much better than Forte, so give it a look.
You can do a combined download of ONE plus the JDK 1.4, at a total
of 100 Meg.
One way around the brutally large downloads is to buy the wares
on CD from Sun.
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BlueJ
You can get BlueJ
for free, but it's pretty light-weight and not a powerful tool.
The dialogs are hard to use. One nice feature, though, is that
it automatically generates a UML diagram of the classes in your
code.
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VisualAge for
Java from IBM
You can download a
free copy of this at
IBM's VisualAge Download. Note that you need to look
for the "Entry Edition" version, and that you may need
to fill out some registration dialogs.
You have to download two files for the build, the "disk 1"
and "disk 2". The software is solid and seems to run
well.
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Visual Cafe (Out of business)
Borland JBuilder
I've used this some. It's not bad. It has the a high-RAM
requirement, but it supports any JDK you like. Check it
out at the JBuilder
site, I think you can get a free trial version.
Metrowerks
I bought a copy of this for
$120, and spent an afternoon trying to build an applet from exiting
code I had, and I couldn't. The help files aren't helpful, the
fonts are ugly, and I'm sorry I spent money on it.
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Microsoft J++ (Obsolete)
This Java compiler is
on some machines in our lab, but is being phased out in favor
of Sun One. In addition, you can rent an installation disk
for J++ from the SJSU bookstore for $30 for four days, and install
J++ on your home machine. A nice thing about commercial software
is that you get the whole thing on one CD and don't have to do
any downloads. JDK, IDE, documentation, all on one handy
disk.
J++ is a very nice IDE.
It seems to run easily on most machines, and doesn't require that
you have a lot of RAM. The catch is that J++ doesn't
support JDK 1.2 and higher. Given that JDK 1.2 doesn't run
on many browsers, this isn't as a big a handicap as you might
think. And for the code we're going to be writing, JDK 1.1
is close enough to JDK 1.2 for most programs.
Even so, it is annoying
not to have the latest and greatest version of Java and for many
people, Microsoft's pig-headed and quixotic refusal to support
JDK 1.2 and higher is a show-stopper.
Rumor has it that Microsoft
will soon make a new Java compiler of some kind called J#.
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The Asteroids Applet
This was the main project in the Fall, 1999 semester,
and is a substantial Java videogame project.
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