[logback-user] Trouble with varargs output

Hi all, I am trying to use logback 1.1.3 with slf4j 1.7.12. This is my log statement: logger.debug("%s %d, %d", "a", 1, 2); The logger is a static constant: private static final Logger logger = LoggerFactory.getLogger(TTSGrammarTest.class); The output of the log statement is: 02:35:16.415 [main] DEBUG test.TTSGrammarTest - %s %d, %d Apparently, the format string and the supplied parameters are not evaluated correctly. I don't have any logging configuration - the program is run under eclipse. Thanks in advance for any help, Arne