NoClassDefFoundError although jar is in classpath

[Felix Natter <fnatter@gmx.net>]

hi,

I am finishing insubstantial (flamingo/substance/trident) and most
r-deps use substance for additional L&Fs, so I just needed to replace
occurrences of:
  org.jvnet.substance.skin.SubstanceAutumnLookAndFeel
with:
  org.pushingpixels.substance.api.skin.SubstanceAutumnLookAndFeel
etc.

This is also the case for "triplea", but it aborts with not being able
to find org.pushingpixels.substance.api.SubstanceLookAndFeel
(which is the abstract base class for the Substance* L&Fs [1]):

[1] this was also the case in the old substance-5.3.

Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError:
   org.pushingpixels.substance.api.SubstanceLookAndFeel
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:191)
        // this is the place where the L&F classes are loaded (see above):
        at games.strategy.common.ui.BasicGameMenuBar.getLookAndFeelList(BasicGameMenuBar.java:844)

triplea builds a runnable jar 'triplea.jar' at /usr/share/triplea/bin.
Its MANIFEST.MF looks like:

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.9.5
Class-Path: /usr/share/java/commons-httpclient.jar /usr/share/java/commo
 ns-logging.jar /usr/share/java/commons-codec.jar /usr/share/java/substan
 ce.jar /usr/share/java/laf-widget.jar /usr/share/java/gnumail.jar /usr/s
 hare/java/upnp.jar
Created-By: 1.7.0_79-b14 (Oracle Corporation)
Main-Class: games.strategy.engine.framework.GameRunner
TripleA-Version: 1_7_0_3

(running java -jar triplea.jar produces the NoClassDefFoundError above)

So /usr/share/java/substance.jar is part of it.
And the class is part of /usr/share/java/substance.jar:

$ jar tf /usr/share/java/substance.jar | grep org.pushingpixels.substance.api.SubstanceLookAndFeel
org/pushingpixels/substance/api/SubstanceLookAndFeel$2.class
org/pushingpixels/substance/api/SubstanceLookAndFeel$3.class
org/pushingpixels/substance/api/SubstanceLookAndFeel$1.class
org/pushingpixels/substance/api/SubstanceLookAndFeel.class
org/pushingpixels/substance/api/SubstanceLookAndFeel$1SkinDerivedLookAndFeel.class

Also, there are no direct references to this class in the source tree:
$ grep -R -i substancelookandfeel *

Does anybody have an idea?

Please tell me if you need additional information.

Thanks and Best Regards,
-- 
Felix Natter