Question

I have an external library(just one class file called org.vinay.dep.DependedClass).It is well within
its package directory structure and directory org is on Desktop.

And I have a jar called a.jar which has dependency on my external lib.

Executing jar -tf a.jar gives below output,

META-INF/                
META-INF/MANIFEST.MF     
com/      
com/os/          
com/os/hw/          
com/os/hw/HelloWorld.class       
com/os/hw/HwUtil.class 

I tried to run the jar in 2 ways

1. java -classpath C:/Users/vinay/Desktop -jar a.jar with
   manifest.mf entries being

   Manifest-Version: 1.0
   Created-By: 1.6.0_05 (Sun
   Microsystems Inc.)
   Main-Class: com.os.hw.HelloWorld

   and got NoClassDefFoundError for DependedClass

2. java -jar a.jar after changing manifest entries as below

   Manifest-Version: 1.0
   Created-By: 1.6.0_05 (Sun
   Microsystems Inc.)
   Main-Class: com.os.hw.HelloWorld
   Class-Path: C:/Users/vinay/Desktop

   But this time it throwed NoClassDefFoundError for HelloWorld
   class itself

When i package my external lib into jar and use the jar name for Class-Path entry in manifest file it works.Is there a way to resolve this problem without packaging external lib into jar?

Answer 1

I don’t think you can combine -classpath and -jar. You can instead do it like this:

java -cp C:/Users/vinay/Desktop;a.jar com.os.hw.HelloWorld

This assumes a.jar is in the current folder (or you can add full path to a.jar as well).

Hardcoding the Class-Path entry of your manifest to a path on your local machine is never the correct solution 🙂