Hello: I am a new subscriber to this list, so please forgive me if these questions have already been asked and answered. Being quite experienced with log4j, migrating to Logback would probably be a relatively easy exercise. However, while reading the manual, I have a few questions, which might be best addressed to the developers, rather than the users. 1) using parameterized logging instead of wrapping the log statment in a conditional isEnabled, is very convenient, however I wonder whether there is an implementation of printf function (or whether there are plans to do so). http://java.sun.com/j2se/1.5.0/docs/api/java/util/Formatter.html#format(java..., java.lang.Object...) Implementation of log statements with such functionality and a variable arg list would be fairly trivial, but I found no references to such in Logback Javadocs, FAQ or search engine queries. 2) If the answer to (1) is NO, then is there an easy way to extend Logback to incorporate such functions? 3) the need to migrate to Logback arose when we started to look into modularizing our application with OSGi Apache Felix. What OSGi bundles of Logback/SLF4J would you recommend? Your response is greatly appreciated. Regards, Pavel Bortnovskiy. Jefferies archives and monitors outgoing and incoming e-mail. The contents of this email, including any attachments, are confidential to the ordinary user of the email address to which it was addressed. If you are not the addressee of this email you may not copy, forward, disclose or otherwise use it or any part of it in any form whatsoever. This email may be produced at the request of regulators or in connection with civil litigation. Jefferies accepts no liability for any errors or omissions arising as a result of transmission. Use by other than intended recipients is prohibited. In the United Kingdom, Jefferies operates as Jefferies International Limited; registered in England: no. 1978621; registered office: Vintners Place, 68 Upper Thames Street, London EC4V 3BJ. Jefferies International Limited is authorised and regulated by the Financial Services Authority.