SETTING CLASSPATH N JAVA

HI ,
I AM LEARNING JAVA, ONE PROBLEM THAT I AM FACING IS HOW TO SET THE CLASSPATH SO THAT I CAN COMPILE AND RUN JAVA FILES PLACED IN DIFFERENT DRIVES OR FOLDERS. THE PROBLEM I HAVE NOW IS THAT I HAVE TO PLACE ALL MY .JAVA FILES IN THE BIN FOLDER IN ORDER TO RUN THEM.

http://java.sun.com/docs/books/tutorial/getStarted/cupojava/win32.html
Javapedia: Classpath
Setting the class path (Windows)
How Classes are Found

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How to set classpath from java class ??

I have tried to use System.setProperty("java.class.path", "my class path string ") to set classpath dynamically. But it is not working. How to set it dynamically from java class ?? Thanks , gary

Look into the java.net.URLClassLoader. You can't set the classpath after the fact but you can specify URL's that will checked when you try to load a class with that loader.

Set classpath from java code

Hi,
Is it possible to set new classpath from java code? Something like System.setClasspath(String);
Many thanks
Miso

You aren't the first one to wonder whether that would work, so don't call yourself stupid on that account.
Not taking 15 minutes to set up and run a test to actually see if it works... well, if you really needed the answer, that would be different.

Starting tomcat server after setting classpath for java

Sorry if this is nothing to do with java, it is more to do with starting tomcat server.
Tomcat server has been working totally fine, but when I wanted to compile a java servlet I wrote for it, I needed to run a BAT file called gojava in MS-DOS that had the classpath for java to work properly. I then attempted to run Tomcat, but just got 'bad command'. As long as I don't start up java by setting the classpath, tomcat will work, but as I need java to write servlets and then to test them without restarting my PC each time, how do I get tomcat to work?
Thanks
Hannah

Sounds like your batch file is changing your path, not your classpath. If you're getting "Bad command or filename" when attempting to run Tomcat, it can't find the executable. Check out the .bat file and see what it's doing (maybe even post it here for further clarity). If it's changing your path at all, make sure it includes a %path% to indicate that it simply wants to append items to the path, not overwrite it completely. Sorry if i'm way off base with my suggestions, but it sounds like that's where the problem's going to be, especially if rebooting resolves the problem.

Setting classpath within java application

Hi
Sorry if this question has already been asked, I've searched for it but couldn't find it.
I've written a class (see below) that when given a directory will add all of the jar files to the classpath.
The classpath is updated to include all of the jar files but if I try to use a class within one of these jar files then an exception is generated stating that the class can't be found.
Can anyone help me with this problem? I thought that I would only need to update the classpath.
Thanks,
Rob
public class Jar {
     public static void addJarsToClasspath(String root) {
          File f = new File(root);
          if (f.exists()) {
               File[] jars = f.listFiles(new FilenameFilter(){
                    public boolean accept(File dir, String file) {
                         return ((String)dir.getName()+file).endsWith(".jar");
               String classpath = System.getProperty("java.class.path");
               for (int i=0; i<jars.length; i++) {
                         classpath = classpath.concat(":"+root+"/"+jars.getName());
               System.setProperty("java.class.path",classpath);
               System.out.println(System.getProperty("java.class.path"));

You can do this with batch files in Windows NT/2000:
1) create a batch file called "setcp.bat" containing the following:
for %%i in (C:\myPath\*.jar) do call appendcp.bat %%i
2) create another batch file called "appendcp.bat" containing the following:
set CLASSPATH=%CLASSPATH%;%1
Now you can run setcp.bat and it will add all JAR files in C:\myPath to your CLASSPATH.
Jesper

Set classpath for java in fedora core 1?

i am new to programming java on linux and im having trouble finding out how to set classpath in the shell, permenently. i have the sdk installed and tried the usual "hello world" test and failed. the response i would get a message telling me javac is not a bash command. i have no clue how to set classpaths in linux so i would much appreciate it if someone would show me thanks

Ok, there is two ways to achieve this. Either by setting it globally for all the user, or only for your self. If you are working on your own station and have super user access, you can set it up for all th eusers, if not, just set it for your self. How ??
for all the users, modify the file /etc/profile and include this:
PATH=$PATH:/path/to/jdk/bin:.
CLASSPATH=$CLASSPATH:/path/to/jdk/lib/tools.jar:/path/to/jdk/lib/rt.jar
export PATH CLASSPATH
If you want to add it only for ur self then, modify the lsame line in ~/.bash_profile
hope this helps

Setting Classpath for java in UNIX machine

Hi
I need to work in JAVA in UNIX machine. But, I don't know how to set the classpath in the unix machine. If anyone knows, please let me know.

setenv CLASSPATH .:/homes/code:${CLASSPATH}
http://www.cise.ufl.edu/class/cop3530fa04/WinHowTo.htm

How to set classpath from java application

in my ian using Runtine.exec();
here the code
String cmd[]={"cmd.exe","/c","path=C:\\j2sdk1.4.2_03\\bin\\;"};
          Runtime runtime = Runtime.getRuntime();
          Process setPathProc = runtime.exec(cmd);
          Process proc = runtime.exec("javac "+path+"\\"+clsname+".java");
it working when ian running the application class from command, but when iam creating a jar file and running it was not working,,
any suggestion

hi kaj,
my problem is ,
In my application i have to compile one java file and
create class file for that java file, here before
creating i have to set class path, am i right?
so in my program only first i have to set class path,
and later i have to compile, so, in my code i have
mentioned the details about to set class path and
compile the program, r u getting what iam telling,
please help me, if u know anything,
thanks

Can we set classpath dynamically

Is it possible to set Classpath from java code .. Before executing a Java class we can set classpath manually using set classpath option in windows .. But here i want to do that from java code .. not thru this dos command.. is there any java API's to do this ??

Hey its possible ..
File afile = new File (MyJarName);
URL rl = new URL (afile.toURL().toString());
URL [] ury = new URL [] {rl};
URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
Class sysclass = URLClassLoader.class;
Method method = sysclass.getDeclaredMethod("addURL", new Class[]{rl.getClass()});
method.setAccessible(true);
method.invoke(sysloader, new Object[] {rl});
String Classpath = System.getProperty("java.class.path");
System.out.println("Before->"+Classpath);
Classpath = Classpath + System.getProperty("path.separator") + rl.toString();
System.setProperty("java.class.path", Classpath);
Classpath = System.getProperty("java.class.path");
System.out.println("After->"+Classpath);

Set system classpath using java program??

Hi,
I want to set the System classpath using java program. Can somebody please tell how to do this.
Prashant

but this will set the classpath for that particular JVM only.
Isn't it??? I want that of SYSTEM so that user can access that class path from any JVM instance.
Prashant

Setting classpath in IBM VisualAge for Java Programming

Hai,
How to set classpath in IBM visualAge3.5 to run the Java programs
Please respond immd..
Thanx in advance

Right click on the class whose path you need to set; then click the classpath tab and enter the classpath in the textfield provided.

Set CLASSPATH does not work, how do I run java.exe?

Hi guys,
I have a problem running the java.exe and I'm using Win XP. Here is my problem:
Under the command prompt, I set the path: path = C:\Program Files\Java 2\j2sdk1.4.2_05\bin
Then I created a folder in E:\Hello. I save my Hello.java in that folder, and I compiled it:
javac Hello.java
Now, there is a Hello.class created in that folder.
Then I try to run it: java Hello
but I got an error: "Exception in thread "main" java.lang.NoClassDefFoundError: Hello"
So, I try to set CLASSPATH, however, the problem remains, no matter how hard I try.
Any ideas?

None of the suggestion worked, I wonder why???
Here is my location for the JDK:
C:\Program Files\Java 2\j2sdk1.4.2_05\bin
Here is my location for my Java project file:
E:\JavaProject\Hello
Here is the file name:
Hello.java
Here is the command prompt:
C:\Documents and Settings\Alex Ngai> e:
E:\> cd JavaProject
E:\JavaProject> cd Hello
E:\JavaProject\Hello> path = C:\Program Files\Java
2\j2sdk1.4.2_05\bin
E:\JavaProject\Hello> javac Hello.java
E:\JavaProject\Hello> java Hello
Exception in thread "main"
java.lang.NoClassDefFoundError: Hello
E:\JavaProject\Hello> java -cp Hello
// Does not work, it lists all of the options for java
E:\JavaProject\Hello> set CLASSPATH =
E:\JavaProject\Hello
CLASSPATH="C:\Program
Files\Java\j2re1.4.2_04\lib\ext\QTJava.zip"
E:\JavaProject\Hello> java Hello
Exception in thread "main"
java.lang.NoClassDefFoundError: Hello
// I have tried a lot more, none of them won't work!!
Now what should I try in the following command prompt?
E:\JavaProject\Hello>Given the above there is only one possible explaination.
You have a file named "Hello.java".
In that file you have a non-public class which is NOT named "Hello". Instead it is named something like "HelloWorld" or even "hello" (case matters.)

Problems in setting classpath in vista

i am using Xp pro and Vista.
My issue is that I am not able to set classpath in vista.
i want to set classpath so that I can compile and run programs from different folder other than default one in which java is installed.
Please help.

i am using Xp pro and Vista.
My issue is that I am not able to set classpath in
vista.
Don't worry about it. The CLASSPATH variable is best avoided anyway. Specify classpaths for particular apps on the command-line. Teh Docs show you how
i want to set classpath so that I can compile and run
programs from different folder other than default one
in which java is installed.
Please help.This suggests you're talking about PATH rather than classpath. Do you understand the difference?

Setting Classpath in linux

Hi !! Can anyone help me in setting classpath in linux to run servlets/? I tried using this command..but didnt work
export CLASSPATH="$CLASSPATH:/usr/share/tomcat5/server/lib/servlets-common.jar"
Thanks
Nive

in ur autoexec.bat file write the following
set PATH=C:\jdk1.5.0_04\bin;%PATH%
set JAVA_HOME=C:\jdk1.5.0_04
set
CLASSPATH=.;C:\jakarta-tomcat-5.5.9\common\lib\servlet
-api.jar;C:\jakarta-tomcat-5.5.9\common\lib\jsp-api.ja
r;C:\Servlets+JSP;..;..\..;C:\jakarta-struts-1.2.4\lib
\struts.jarThis response is meaningless. Principally because the OP specifically mentioned the use of LINUX. Not Windows.
I've taken the advice of other forum users by avoiding a system level classpath variable. I define the classpath each time I compile and run. Working on Linux I tend to use command line argument files ( http://java.sun.com/j2se/1.5.0/docs/tooldocs/solaris/javac.html#commandlineargfile ) which eliminates the need to redefine the classpath each time I compile or run my classes and apps. But others may do things differently.
Here is a website you might want to check out which pertains to setting the classpath on Solaris and Linux.
http://java.sun.com/j2se/1.5.0/docs/tooldocs/solaris/classpath.html

Help with setting classpath

Hi All,
I am new to servlets and JSP. I have a question regarding setting Classpath. My development directory structure is like this c:\..\desktop\java\project1\src\com\eg\web\e1.java. Servlet.jar file is in C:\Program Files\Apache Group\Tomcat 4.1\common\lib. I tried setting Classpath in windows 2000 using control panel=>System utility by this command
SET CLASSPATH=.;c:\Program Files\Apache Group\Tomcat 4.1\common\lib\servlet.jar . I try to compile my program by going into the whole development directory structure C:\..\src\com\eg\web using javac e1.java. But I get the error "package javax.servlet does not exist". Can somebody help me resolve this?
Thank You in advance
Jaya

Question 1: Are you using an IDE?
[IDEs ignore the system classpath]
Question 2: Did you try setting the classpath using the -cp option for javac, if you are not using an IDE?
[you could also try to print the classpath on command line to check if it has taken effect]

SETTING CLASSPATH N JAVA

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