JavaEE Web Project > Run As > Maven not working - constraint violation: javax.servlet-api 3.1.0 and javax.servlet 3.1.0.v201410161800 ------------------------------------------------------------------------------------------------------------------------------------- Key: JBDS-4149 URL: https://issues.jboss.org/browse/JBDS-4149 Project: Red Hat JBoss Developer Studio (devstudio) Issue Type: Bug Components: maven, rpm Affects Versions: 10.2.0.AM3 Environment: RHEL7 64bit Reporter: Lukáš Valach Assignee: Nick Boldt Priority: Critical Fix For: 10.2.0.AM3 Attachments: ClassNotFoundEx_20161102_095940.png, eclipse.log, eclipse_10.2-0.20161101.1258.log, javax.servlet.310rpm_vs_orbit.png, rh-eclipse46-devstudio-snapshots-10_2.repo, rh-eclipse46.repo I am not able to use embedded Maven. When I try to run Maven clean (or whatever else) I get following error message: {code} Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/Logger at java.lang.Class.getDeclaredMethods0(Native Method) at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) at java.lang.Class.privateGetMethodRecursive(Class.java:3048) at java.lang.Class.getMethod0(Class.java:3018) at java.lang.Class.getMethod(Class.java:1784) at org.codehaus.plexus.classworlds.launcher.Launcher.getEnhancedMainMethod(Launcher.java:172) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:268) at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356) Caused by: java.lang.ClassNotFoundException: org.slf4j.Logger at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50) at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:271) at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:247) at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239) ... 10 more {code} Standalone maven installation works fine.