Hints on getting the commands  javac  and  java  to run
from your DOS command prompt, for WINDOWS XP:

The information on your Java installation gives this
information, see the following webpages (following links):

file:///C:/j2sdk1.4.2_05/README.html
http://java.sun.com/j2se/1.4.2/install.html

and here are more details concerning a Windows XP operating
system:
http://java.sun.com/j2se/1.4.2/install-windows.html#install

from that webpage:

    5. Update the PATH variable (Optional)

    You can run the Java 2 SDK without setting the PATH
    variable, or you can optionally set it as a convenience.

    Should I set the PATH variable?
    Set the PATH variable if you want to be able to
    conveniently run the Java 2 SDK executables (javac.exe,
    java.exe, javadoc.exe, etc.) from any directory without
    having to type the full path of the command. If you don't
    set the PATH variable, you need to specify the full path to
    the executable every time you run it, such as:

    C:> \j2sdk1.4.2_<version>\bin\javac MyClass.java

    It's useful to set the PATH permanently so it will
    persist after rebooting.

    How do I set the PATH permanently?
    To set the PATH permanently, add the full path of the
    j2sdk1.4.2_<version>\bin directory to the PATH variable.
    Typically this full path looks something like
    C:\j2sdk1.4.2_<version>\bin. Set the PATH as follows,
    according to whether you are on Microsoft Windows NT or
    98/2000/ME.

    Microsoft Windows NT, 2000, and XP - To set the PATH
    permanently:

       1. Choose Start, Settings, Control Panel
..... and here are the additional details:
in XP, continue as follows, clicking:
     - Performance and Maintenance
     - See basic information about your computer
     - Advanced
     - Environment Variables
     - System Variables
     - path
     - edit
       now append to the current path (without deleting what
       is already there) the text (possibly replacing _05
       by a later version):
       ;C:/j2sdk1.4.2_05/bin
     - click OK, OK

The path should now refer to the Java environment as soon as
you open a new DOS command shell, by typing CMD from
Start -> Run.  You can see it by typing "PATH" at the command
prompt, as in this example:

C:\Documents and Settings\User>path
PATH=C:\texmf\miktex\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem
;c:\j2sdk1.4.2_05\bin

C:\Documents and Settings\User>