title: JBoss java.lang.LinkageError when deploying EAR
body: <p>I'm deploying an ear to JBoss and when I start the server I get this exception thrown:</p>
  
  <pre><code>Caused by: java.lang.LinkageError: loader constraint violation in interface itable initialization: when resolving method "ch.qos.logback.classic.LoggerContext.getLogger(Ljava/lang/String;)Lorg/slf4j/Logger;" the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, ch/qos/logback/classic/LoggerContext, and the class loader (instance of org/jboss/modules/ModuleClassLoader) for interface org/slf4j/ILoggerFactory have different Class objects for the type ;)Lorg/slf4j/Logger; used in the signature
  </code></pre>
  
  <p>I have an EAR project and in the deployment assembly I include logback-classic/logback-core/ and slf4j-api. When I do this, the three jars automatically get placed in the EAR Libraries folder in the build paths of 2 other ejb projects (which are both packaged as jars and referenced in the deployment assembly of the EAR)</p>
  
  <p>not sure why this is happening.. Also, when I dont put the jars in the deployment assembly of the EAR, I link them in the build path of the 2 ejb projects directly, but when I deploy the ear JBoss throws <code>noClassFound exception</code> on slf4j/Logger.. </p>
  
  <p>any ideas?</p>