Hello, I just made an API abstraction above logback in order to add specific functions in this api i have all logback functions (juste overrided with no changes) and add some other functions (with specific signature) : I created then a file appender and a JMS appender in logback.xml (nothing special) I am using activemq for jms MOM. The problem is then : when a run a test class with some methodes invocation i see this message : SLF4J: The following loggers will not work becasue they were created SLF4J: during the default configuration phase of the underlying logging system. SLF4J: See also http://www.slf4j.org/codes.html#substituteLogger SLF4J: org.apache.activemq.ActiveMQPrefetchPolicy SLF4J: org.apache.activemq.jndi.ReadOnlyContext SLF4J: org.apache.activemq.transport.tcp.TcpTransportFactory SLF4J: org.apache.activemq.util.ServiceSupport All user logs are logged as expected but i dont see any of activemq (or other framework) logs . i have read the information in slf4j url but don't understund what they mean and how to correct this problem in logback . Thanks for any help