OOP-1, jr.jar, and the classpath on OSX (10.7.5)

[Steven Lacher]

I've read that you can put JAR files on a mac in /System/Library/Java/Extensions and they become available to the JVM.

But I put jr.jar in there, and it doesn't seem to be recognized.

This code compiles:

import com.javaranch.common.*;
public class DaysOld
{
public static void main (String [] args)
{
GDate dateIn = new GDate();

System.out.println( "just a stub" );
}
}

But when I run it, the class isn't found

java.lang.NoClassDefFoundError: com/javaranch/common/GDate
at DaysOld.main(DaysOld.java:6)
Caused by: java.lang.ClassNotFoundException
at edu.rice.cs.plt.reflect.PathClassLoader.findClass(PathClassLoader.java:148)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 1 more


Am I missing something?

[Steven Lacher]

Turned out I WAS missing something.

I'm using the DrJava IDE to write my code. It's a simple IDE without lots of fancy bells and whistles. HOWEVER, it does have its own classpath settings. I put the jar in the top level folder I'm using for the cattledrive, and then used the preferences/resource locations command to add the jr. jar.

Voila!

I also tested just using the terminal, after adding a .bashrc file to my drive, as follows:

Use a text editor (e.g., TextEdit) to add the following line to the file /Users/username/.bashrc.

export CLASSPATH=.:/Users/username/cattledrive/

(or wherever it is you're keeping the jr.jar.)

[Marilyn de Queiroz]

Thanks, Steven. That's a good note to share.