Thanks, @maxim.
So far, to use compressed input/output for Workflows and Activities, we were using byte. We have changed that to use actual objects and using a custom DataConverter that uses GZIPInputStream/GZIPOutputStream for compressing/decompressing the input/output.
The code is much cleaner now. However, we are still trying to figure out how to get the original (uncompressed) input/output for debugging. I looked at cryptconverter. It looks like it will work only with tctl.
Since we have already written a DataConverter, can we use that with some Java-SDK API to get the uncompressed input/output? For example. can we use the DataConverter with WorkflowServiceStubs.getWorkflowExecutionHistory()?