Hi Does anybody know if it is it possible to use Logback on JDK1.4? I get an UnsupportedClassVersionError when trying to instantiate a Logback logger through SLF4J. I've had a look at pom.xml and see that the jdkLevel is set to 1.5. So the exception makes sense - I'm trying to run 1.5 code against a 1.4 jdk... That said I find it strange the Logback only supports jdk1.5 and higher. Anybody running it against a 1.4 jdk? If so, how did you manage to do it? Thanks. To be complete: The code that I'm using is very simple: Logger log = LoggerFactory.getLogger(InitLog.class); log.debug(">>> Logging Initialized"); The exception I'm getting: java.lang.UnsupportedClassVersionError: org/slf4j/LoggerFactory (Unsupported major.minor version 49.0) at java.lang.ClassLoader.defineClass0(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java(Compiled Code)) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java(Compiled Code)) at com.ibm.ws.classloader.CompoundClassLoader._defineClass(CompoundClassLoader.java:446) at com.ibm.ws.classloader.CompoundClassLoader.findClass(CompoundClassLoader.java(Compiled Code)) at com.ibm.ws.classloader.CompoundClassLoader.loadClass(CompoundClassLoader.java:300) at java.lang.ClassLoader.loadClass(ClassLoader.java(Compiled Code)) at za.ibm.slftest.servlet.InitLog.init(InitLog.java:15) Regards Fouche du Preez