I just downloaded the sources of WildFly Core and WildFly. The compilations are working fine. However, for WildFly I'm getting these warnings right at the beginning: [WARNING] Some problems were encountered while building the effective model for org.wildfly:wildfly-ts-integ-smoke:jar:9.0.0.Alpha1-SNAPSHOT [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.jboss.arquillian.junit:arquillian-junit-container:jar -> duplicate declaration of version (?) @ org.wildfly:wildfly-testsuite:9.0.0.Alpha1-SNAPSHOT, C:\temp\wildfly-master-20140703\testsuite\pom.xml, line 215, column 21 [WARNING] [WARNING] Some problems were encountered while building the effective model for org.wildfly:wildfly-ts-integ:pom:9.0.0.Alpha1-SNAPSHOT [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.jboss.arquillian.junit:arquillian-junit-container:jar -> duplicate declaration of version (?) @ org.wildfly:wildfly-testsuite:9.0.0.Alpha1-SNAPSHOT, C:\temp\wildfly-master-20140703\testsuite\pom.xml, line 215, column 21 [WARNING] [WARNING] Some problems were encountered while building the effective model for org.wildfly:wildfly-testsuite:pom:9.0.0.Alpha1-SNAPSHOT [WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.jboss.arquillian.junit:arquillian-junit-container:jar -> duplicate declaration of version (?) @ line 215, column 21 [WARNING] [WARNING] It is highly recommended to fix these problems because they threaten the stability of your build. [WARNING] [WARNING] For this reason, future Maven versions might no longer support building such malformed projects.