When openjpa.Log is set to slf4j, OpenJPA will delegate to SLF4J API for logging, which provides several adapters or a simple logging mechanism. For further details on logging adapters and configuring SLF4J, please see the SLF4J website.

Note, as SLF4J does not provide a FATAL log level the SLF4JLogFactory will map it to the ERROR log level.