the error happens with this commit: mkristian/nexus-oss@add54bd

steps to reproduce (needs maven-3.0.x):

git clone --branch little-update git@github.com:mkristian/nexus-oss.git
cd nexus-oss/plugins/rubygem
mvn install

the first ScriptingContainer instance works, the second loads the jar and finds the ExtensionClass but does not load the extension class anymore.

some fails running the same code inside the nexus server.

try to narrow down the reproduction case further.