Steps to reproduce

1.  Import the sample classes (com.baloise.actions.HelloWorldDefinition and com.baloise.actions.HelloWorld) in the groovy app: scripts.com.xml
2.  Configure a new action in, for example, contacts app that uses the groovy classes. config.modules.contacts.apps.contacts.subApps.browser.actions.sayHello.xml
3. Add new action to the action bar.
4. Open contacts app

Expected results

When opening the app, the new action appears and when clicking on it, the message is printed

Actual results

When opening the app, there's an error

Workaround

Using classes from a maven module

Development notes

This seems to be related to ByteBuddy, specifically ByteBuddyI18nizer. In fact, when using a groovy class for a command, as this example, it works ok since byte buddy is not involved. Besides, in 5.7 it does not happen.
This is the stack trace

ERROR agnolia.ui.framework.app.AppInstanceControllerImpl: Sub-app [browser] of app [contacts] failed to start
java.lang.IllegalArgumentException: Could not create type
	at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:154) ~[byte-buddy-1.10.8.jar:?]
	at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:365) ~[byte-buddy-1.10.8.jar:?]
...
Caused by: java.lang.ClassNotFoundException: com.baloise.actions.HelloWorldDefinition
	at net.bytebuddy.dynamic.loading.ByteArrayClassLoader.findClass(ByteArrayClassLoader.java:348) ~[byte-buddy-1.10.8.jar:?]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_121]