NoClassDefFoundError (Could not initialize class org.apache.log4j.Log4jLoggerFactory) - eclipse

Question

I have a maven project under Eclipse Luna SR2 (4.4.2). This project uses slf4j through maven dependencies.
Infinitest is running continuous integration and it works in a lot of case, except for static slf4j declarations as
#Component
public class UnitProcessor implements Processor {
private static Logger logger = LoggerFactory.getLogger(UnitProcessor.class);
...
where I got this message
NoClassDefFoundError (Could not initialize class org.apache.log4j.Log4jLoggerFactory)
Of course, there's no exception nor problem in Eclipse itself when I run involved class. No problem in maven too.
Infinitest console wrote :
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/mde.DSI/.m2/repository/org/slf4j/slf4j-log4j12/1.5.10/slf4j-log4j12-1.5.10.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/C:/Users/mde.DSI/.m2/repository/ch/qos/logback/logback-classic/1.1.3/logback-classic-1.1.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
SLF4J: The requested version 1.5.10 by your slf4j binding is not compatible with [1.6]
SLF4J: See http://www.slf4j.org/codes.html#version_mismatch for further details.
SLF4J: Detected both log4j-over-slf4j.jar AND slf4j-log4j12.jar on the class path, preempting StackOverflowError.
SLF4J: See also http://www.slf4j.org/codes.html#log4jDelegationLoop for more details.
How to get out of this hell ?
Thanks