Can you share a bit more about your code?
After you’ve successfully loaded your keras model, it isn’t really much different from a model that was created with dl4j. So it being a keras model originally shouldn’t be the origin of the error.
Unfortunately the JVM crashed hard enough that it can’t even collect a proper stack trace here, but from the other entries in the log, it looks like you are using this in a concurrent context. Can you tell us more about that?