Hello everyone. I posted same message to slf4j-user mailing list 2 months ago, but I have no answer yet. I think that "LocationAwareLogger#log(...)" function in "slf4j-jdk14.jar" is not working. --------------------------------------------------------------------------------- logger.log(null, "test.Test", INFO_INT , "Hello {}", "World"); --------------------------------------------------------------------------------- prints "Hello {}", not "Hello World". in JDK14LoggerAdapter.java, "argArray" parameter is not used in the function. ------------------------------------------------------------------------------------------------------------------------------------------------ public void log(Marker marker, String callerFQCN, int level, String message, Object[] argArray, Throwable t) { Level julLevel = slf4jLevelIntToJULLevel(level); // the logger.isLoggable check avoids the unconditional // construction of location data for disabled log // statements. As of 2008-07-31, callers of this method // do not perform this check. See also // http://jira.qos.ch/browse/SLF4J-81 if (logger.isLoggable(julLevel)) { log(callerFQCN, julLevel, message, t); } } ------------------------------------------------------------------------------------------------------------------------------------------------ Is this a bug? -- I'm Sorry , and thanks for reading my poor English.