This error is common with JBoss module dependencies. I fixed this issue by adding jboss-structure.xml to my src project directory and adding the missing module to the dependencies node. An example of the file's content is below: <?xml version="1.0" encoding="UTF-8"?> <jboss-deployment-structure> <deployment> <dependencies> <module name="location.missingdependency.jar" services="export" /> </dependencies> </deployment> </jboss-deployment-structure> Just to mention that this issue was experienced with the EJB jar. For a normal jar/WAR file, a manifest.ft file will do.