how to run a class in the jar file which is in the classpath of another jar file

Question

I have a jar file called "a.jar" which has another jar file called "b.jar".

a.jar
 |
 |-- META-INF
 |     |
 |     |-- MANIFEST.MF
 |
 |-- b.jar
     |
     |- com/test/MainInB.class

"b.jar" has com/test/MainInB.class file. (MainInB class just print out "hello world!")

"a.jar" has the MANIFES.MF like this:

Manifest-version: 1.0
Main-Class: com.test.MainInB
Class-Path: b.jar

(The manifest file does end with empty new line)

---

And I would like to run the a.jar like this so it prints out "hello world!"

java -jar a.jar

But I got NoClassDefFoundError!

Please Help! Is this not allowed? Or am I missing something?

R Joe

Answer 1

Java have a issue it can not read jars from inside of jar file.

They considered it for the future release. But not fixed till now see BUG .

You have to keep them again in lib

Answer 2

Actually my example works!

I'm just having problem with my project in which I use maven-assembly-plugin to create jar and MANIFEST.MF.

Something must be off in the configuration or the plugin.

Thanks anyway guys!

Joe