We have a functioning producer that uses <byte[], byte[]> as the Producer
and KeyedMessage signature. We specify the DefaultEncoder in the
properties. In Java 1.6 it works fine. However, under Java 1.7 it gives the
following error:

Failed to collate messages by topic, partition due to: [B incompatible with

If we change the signature to <String, String>, change the byte arrays
we're passing to strings, and change the encoder to StringEncoder then
things work just fine.

Has anyone encountered something like this before?