expanding cluster and reassigning parititions without restarting producer

Hi All,
I recently had an issue producing from python where expanding a cluster
from 3 to 5 nodes and reassigning partitions forced me to restart the
producer b/c of KeyError thrown.
Is this situation handled by the Java producer automatically or need I do
something to have the java producer refresh itself to see the reassigned
partition layout and produce away ?
Shlomi