Following the instructions from https://docs.jboss.org/author/display/FORGE/Implement+the+Plugin+interface, when executing the following :

plugins new-plugin --named Wro4jPlugin

Forge produces :

Picked up type <JavaResource>: org.wro4j.forge.WroJPlugin
Wrote /path/to/workspace/plugin-wro4j/src/main/java/org/wro4j/forge/WroJPlugin.java

The 4 has been removed, 'j' capitalized. This is caused by some bad regexp in https://github.com/forge/core/blob/master/dev-plugins/src/main/java/org/jboss/forge/dev/PluginsPlugin.java#L125