Description of problem: EAP 6.4.0.DR3 contains netty 3.6.10.Final but HornetQ tag 2.3.21.Final depends on netty 3.6.9.Final. Those versions should be in sync.
Netty versions are not in sync in EAP 6.4.0.DR8 (HQ 2.3.23.Final).
Fixed on 2.3.x via c91a9170bfcf53c1a3cb946f3e760e5865cb0ef9.
It's synced in EAP 6.4.0.DR11. Thanks!