The mongodb shell allows to rename a collection and optionally drop the target. It would be great to be able to do this in the java driver, too. I.E.:
public DBCollection rename( String newName, boolean dropTarget )
throws MongoException

{ CommandResult ret = _db.getSisterDB( "admin" ) .command( BasicDBObjectBuilder.start() .add( "renameCollection" , _fullName ) .add( "to" , _db._name + "." + newName ) .add( "dropTarget", dropTarget) .get() ); ret.throwOnError(); resetIndexCache(); return _db.getCollection( newName ); }