javaDOStips.htm
05-06-2002 Bikle
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Java DOS Tips

Working with Java command line utilities seems to work better inside a UNIX
shell than inside an MS-DOS shell.

The problem is, sometimes I cannot steer clear of the MS-DOS shell during
my day to day work.

I list some .bat files below which help me keep my memory fresh when I'm
working inside an MS-DOS shell.

A demo script of transforming a .java into a .class using javac.exe:

javacDemo.bat

Ideas to note:

-Comments start with the string "rem" or "REM"
-Set a variable using syntax like this:
 set JAVA_HOME=e:\jdev32\java1.2
-Reference the variable using the % character on BOTH sides of the variable:
 set CLASSPATH=%JAVA_HOME%/jre/lib/rt.jar
-If x.java depends on y.java which depends on x.java, place them both on the
 javac.exe command line:
 "%JAVA_HOME%\bin\javac.exe" -classpath "%CLASSPATH%" x.java y.java
-Notice that I make use of double quote (") when I want a variable expanded
 inside of a path and then make that path part of a command.
-Take note that the CLASSPATH tokens are separated by semi colons
 rather than colons (unlike UNIX).
 DOS demo: 
    set CLASSPATH=\a\path\to\a\x.jar;\another\path\to\somejar.jar
 UNIX demo:
        CLASSPATH=/a/path/to/a/x.jar:/another/path/to/somejar.jar



Once I get all my .class files created, I can use them to create a .jar file.

A demo script:

jarDemo.bat

Once the .jar file is created, I can move it to a directory where I
like to put many of my .jar files: c:\jar. Then, I can place its
location in a CLASSPATH variable and use that variable in a Java
command line:

javaDemo.bat

One of the main points I want to make here is that when I work with Java
in the MS-DOS command line environment, I make use of scripts instead of
working directly in the shell like I do in a UNIX shell.

Also, it is important to have access to a decent editor.  I'd suggest
you steer clear of MS notepad.	If you are in a big hurry, download a copy
of TEdit from here:

http://download.com

If you want an editor which will edit just about ANYTHING (even binary files)
get a copy of emacs:

http://ftp.gnu.org/gnu/windows/emacs/latest/

Emacs comes with a learning curve and an appetite for disk space
(about 30mb); it may not be for you.

I happen to like emacs so I recommend that you learn it.  If you are a
command line kind of a person who likes to write scripts rather than
deal with life via wizard, I recommend you get a copy of cygwin for
your PC.  A description from their website http://cygwin.com:

Cygwin is a UNIX environment, developed by Red Hat, for Windows. 

It consists of two parts: A DLL (cygwin1.dll) which acts as a UNIX
emulation layer providing substantial UNIX API functionality.

A collection of tools, ported from UNIX, which provide UNIX/Linux look
and feel.

The Cygwin DLL works with all non-beta, non "release candidate", ix86
versions of Windows since Windows 95, with the exception of Windows
CE.