If GMongo is in use by an application using grails-mongeez, the following GroovyRuntimeException was thrown when accessing the MongeezController's default action:
Ambiguous method overloading for method com.mongodb.DBCursor#sort. Cannot resolve which method to invoke for [class com.mongodb.BasicDBObject] due to overlapping prototypes between: [interface com.mongodb.DBObject] [interface java.util.Map]
This happens because GMongo adds a sort method to DBCursor that accepts a Map argument, and the BasicDBObjectMongeezController was passing to DBCursor#sort implements both the MapandDBObject interfaces. Casting the argument as a DBObject ensures that the "vanilla" DBCursor#sort(DBObject) method is called at runtime, which should work fine whether GMongo is in use or not.