Hi,
strange, because such class cast exception on same class can only mean inconsistency in the JRE. It means, there are 2 incompatible implementation of the class in the class loader.
Hard to explain in a system where no debugging and hot code replacement was done. In short, such situation should not happen in running system.
the solution (which I know and can help) would be to make a platform restart.
Karol
P.S. if you would have full callstack from the log file, we could at least see the calling service.