@Override
      public Void answer(InvocationOnMock invocation) throws Throwable {
        org.apache.logging.log4j.core.LogEvent logEvent =
          invocation.getArgument(0, org.apache.logging.log4j.core.LogEvent.class);
        level.set(logEvent.getLevel());
        msg.set(logEvent.getMessage().getFormattedMessage());
        return null;
      }
This should be in the hbase-logging module but the {@link HBaseClassTestRule} is in hbase-common
so we can only put the class in hbase-common module for now...
hbase-common/src/test/java/org/apache/hadoop/hbase/logging/TestJul2Slf4j.java