The relevant file: https://github.com/hibernate/hibernate-orm/blob/master/documentation/src/main/asciidoc/topical/logging/Logging.adoc

The documentation states that the jboss logger will "search the ClassLoader for the availability of classes that indicate one of the above "providers" being available." Slf4j is one of the listed providers, but jboss logging will only use Slf4j if it is using logback.

jboss logger code here: https://github.com/jboss-logging/jboss-logging/blob/master/src/main/java/org/jboss/logging/LoggerProviders.java

Relevant snippet:

        try {
            // only use slf4j if Logback is in use
            Class.forName("ch.qos.logback.classic.Logger", false, cl);
            return trySlf4j(null);
        } catch (Throwable t) {

The documentation should mention this limitation of the jboss logger.