RHQ server plugin: synchronize data operation String casting to Byte array fails

Invocation of rolling upgrades related operation – Synchronize Data – on a new node's cache fails with a following error:

java.lang.Exception: JBAS011002: Failed to invoke operation: java.lang.String cannot be cast to [B, rolled-back=true
at org.rhq.core.pc.operation.OperationInvocation.run(OperationInvocation.java:278)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)

Note, that there is also ISPN-4447 which says, that we can't record known global keyset using RHQ.

In this issue, we proceed that operation using CLI interface console in order to create dumped keys. Then, we tried to synchronize data using RHQ cache operation and passing "hotrod" as a migrator. This was expected to work properly.