How to trace SQL requests for H2 in-memory databases?

I'm not completely sure, but according to my test it seems if you remove TRACE_LEVEL_SYSTEM_OUT=3 then it would work. Could you try this? Example database URL:

jdbc:h2:mem:test;TRACE_LEVEL_FILE=4

instead of

jdbc:h2:mem:test;TRACE_LEVEL_FILE=4;TRACE_LEVEL_SYSTEM_OUT=3

http://www.h2database.com/html/features.html#trace_options