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Classpath question

Lubosh O
Greenhorn

Joined: Jan 02, 2002
Posts: 2
I am running JDK1.3.0_02 version on a win95 OS. At the beginning I do not have any classpath declared. My java works fine until I explicitly delcare the classpath in my command window. If I declare:
CLASSPATH=C:\JDK1.3.0_02 the execution of my classes with main methods will not work anymore.
Cindy Glass
"The Hood"
Sheriff

Joined: Sep 29, 2000
Posts: 8521
The classpath should point to the \lib directory under that directory if you want the system to find any of the classes that are in the Sun jar files.
Do try to keep your stuff somewhere else, and add that directory to your classpath.
Chun Wong
Greenhorn

Joined: Jan 11, 2002
Posts: 3
I also don't understand CLASSPATH. I am using
win98 and I don't set up any CLASSPATH in
autoexec.bat or somewhere else. All I have
set up is just the path points to c:\jdk1.3.1\bin
that I can use "javac file.java" anywhere...
My question is how come "import java.io.*" works,
even I don't have CLASSPATH set up?
Michael Ernest
High Plains Drifter
Sheriff

Joined: Oct 25, 2000
Posts: 7292

Somewhere along the way, they build the VM so that an environment reference back to the core class files wasn't necessary. That is, no matter what you did to the CLASSPATH, the VM would find its own rt.jar file -- assuming of course, you didn't move or delete it.
And this does make sense. The core classes are "trusted" in the VM above all else, so it shouldn't be possible to accidentally obscure their use.


Make visible what, without you, might perhaps never have been seen.
- Robert Bresson
FinnLady
Greenhorn

Joined: Jan 05, 2002
Posts: 2
Path & Classpath W95/W98: in autoexec.bat (make backup before changes! Just in case!)
Path=C:\JDK1_3\bin;%PATH%;
if the jdk is in file c:\jdk1_3
classpath example below:
SET CLASSPATH=%CLASSPATH%;.;C:\JDK1_3\LIB\TOOLS.JAR;C:\JDK1_3
There can be several lines in autoexec.bat that "set classpath". In classpath you tell the PC where to find tools.jar and then remind it where you installed the jdk
In W2000, if you have installed the jdk to a local (not network) drive: you have to go to Settings, System, then the middle adjustment area (sorry, no W2000 machine here) and then at the top 1/2 of the page is user settings where you add or append the path and classpath. Path to where javac.exe is installed (Example: C:\jdk1_3\bin), classpath to the file tools.jar, starting with period and semicolon (indicarting installation on a local drive).
(Example: .;C:\jdk1_3\lib\tools.jar)
FinnLady
Greenhorn

Joined: Jan 05, 2002
Posts: 2
W2000
Sorry, the place for setting of class & classpath is System, Advanced, then that center button (sorry, can't remember its text), and that opens the page where you can set user & system values (the latter only if you have system admin status).
Marilyn de Queiroz
Sheriff

Joined: Jul 22, 2000
Posts: 9047
    
  10
Originally posted by Lubosh O:
I am running JDK1.3.0_02 version on a win95 OS. At the beginning I do not have any classpath declared. My java works fine until I explicitly delcare the classpath in my command window. If I declare:
CLASSPATH=C:\JDK1.3.0_02 the execution of my classes with main methods will not work anymore.

Your CLASSPATH must point to the subdirectory where your classes are. I am referring to the class you are running (i.e. MyClass.class file).
Without a classpath, you get a default to the directory you are currently in. If you set it to CLASSPATH=C:\JDK1.3.0_02, your class won't run unless you have compiled it to that subdirectory (which most people usually don't do).


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