See JBEAP-17815 for background.

The root of that issue is in MSC-240 some assertions were added to ServiceBuilderImpl to fail invocations if params were null, replacing a previous 'if x == null then do nothing' approach. Since those assertions have been around for a long time now and are reasonable, I think it's fine they stay, but the javadoc for the ServiceBuilder API should note that the params cannot be null.