As described in UG chapter 10, a Groovy project can have a main/java and a main/groovy folder. The first is treated like a normal Java project, the second may contain mixed Java/Groovy code. Therefore the Groovy plugin should not remove the javadoc functionality applied against the main/java folder (what it does now). So we should have a javadoc running against the Java classes in main/java and main/groovy and a groovydoc running against the groovy classes in main/groovy.