LOGBack is the native implementation of SLF4J API. You can download the newest version here: http://logback.qos.ch/download.html
LOGBack and OSGI
Some good news: OSGI Manifests of logback.core and logback.classic bundles are now well defined: all imports and exports work well in all my use-cases.
In previous versions I had to wrap the logback.classic bundle – now you can use logback.core and logback.classic directly from download as good OSGI citizens.
LOGBack is now Dual-Licensed EPL and LGPL
More and more projects recently are using Eclipse Public License and starting with LOGBack Version 0.9.18 LOGBack is dual-licensed using Eclipse Public License (EPL 1.0) and Lesser General Public License (LGPL 2.1).
Read more about LOGBack License here: http://logback.qos.ch/license.html
This is great news for Eclipse Projects :)
I’m using LOGBack as default Logging Framework implementation in redView and open-erp-ware projects. Of course you can use your own implementation, because the only dependency is to SLF4J API.
read more about Logging in OSGI Applications here.