Thread: Running a class outside the directory

Hi everyone!

I have a directories in UNIX:
/home/t_bmf/Java/HelloWorld/src/helloworld :will contain a .java file
/home/t_bmf/Java/HelloWorld/bin :will contain all .class file

let say a have a code:

package helloworld;
 
public class HelloWorld {
 
      public static void main(String[] arg) {
            System.out.println("Hello World");
      }
}

a command to compile this even outside the directory /home/t_bmf/Java/HelloWorld/src/helloworld
javac -d /home/t_bmf/Java/HelloWorld/bin /home/t_bmf/Java/HelloWorld/src/helloworld/HelloWorld.java

this will generate a directory /home/t_bmf/Java/HelloWorld/bin/helloworld
and file inside this is HelloWorld.class

to run this program I must be in directory /home/t_bmf/Java/HelloWorld/bin and using this command:
java helloworld.HelloWorld

Question:
I already how to run the HelloWorld.class, but I must be in helloworld /home/t_bmf/Java/HelloWorld/bin
to run it.
Is there's a way to run the class even when I am not in directory /home/t_bmf/Java/HelloWorld/bin?
let's say I'm in /home/t_bmf, can I still run the HelloWorld.class?

Thank you so much!

Yes. This is a Unix question, not a Java question.

Yes, you can do so by setting the classpath i guess.

Yes, you can do so by setting the classpath i guess.

Thanks, I made it now!
using this command:
java -classpath /home/t_bmf/Java/HelloWorld/bin helloworld.HelloWorld

Thanks for the help!

Anytime

BTW do you know what is the difference between $classpath and -classpath? the command doesn't work with $classpath.
so I guess they are different.

I hope I can open IDE from our server.

I am not sure but according to me -classpath is a command to set the classpath and $CLASSPATH is the environment variable which contains the value of classpath.

Do confirm, not 100% sure.

--- Update ---

to check your current set classpath, you use

echo $CLASSPATH

and if it returns a blank line then it means nothing is set as the classpath.

CLASSPATH=/home/test/class
java -cp $CLASSPATH program

Do confirm, not 100% sure.

I knew it now.
$CLASSPATH is just a variable just like String variables in programming languages.

in my experiment i noticed that i can also create another environment variable just like:
me=/home/t_bmf/

so I can use this variable me whenever I compile or run a program just like:
java -cp $me package.program

I also noticed that to be able to used that environment variable, we need to
include -cp to the command.

Thanks ankurt for your help. this is really helpful.
actually I'm creating a java program that will automatically compile and run another
java program dynamically provided that it has source packages(for .java files), bin packages(for .class files)
and lib folder for jar files(optional). And this must be dynamic since the program cannot tell how many packages
the other program has.
because there is no IDE in our server
I hope you can help me again in my next thread.. Thanks a lot!

Definitely. Everyone here is there to help everyone else.