Java SE (Java Platform, Standard Edition)

Hello,

I have a desktop application needing some jar libraries.
I've exported my application using eclipse exporting wizard, so I've achieved
an app.jar with a simple Manifest.mf (only indicating Main-Class)

I've modified the manifest.mf to include all the jar libraries in the Class-Path.

The manifest.mf looks like this:

Manifest-Version: 1.0
Class-Path: lib/commons-collections-3.1.jar lib/commons-digester-1.7.jar Main-Class: com.pack2.pack2.MainClasse

When I try to execute the application with the command line:
java -jar app.jar

The next exception is thrown:

Exception in thread "main" java.lang.NoClassDefFoundError: pack1/class1
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:539)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:251)
at java.net.URLClassLoader.access$100(URLClassLoader.java:55)
at java.net.URLClassLoader$1.run(URLClassLoader.java:194)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274)
at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)

Can anybody help me please?

Thanks in advance!