java.lang.ClassNotFoundException: org.netbeans.spi.project.ui.ProjectOpenedHook
   at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
   at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
Caused: java.lang.ClassNotFoundException: org.netbeans.spi.project.ui.ProjectOpenedHook starting from ModuleCL@62a77b9f[org.netbeans.modules.scala.maven] with possible defining loaders [ModuleCL@1f7608c7[org.netbeans.modules.projectuiapi.base], ModuleCL@5d4ef27c[org.netbeans.modules.projectuiapi]] and declared parents [ModuleCL@25753412[org.openide.windows], ModuleCL@7f4335c5[org.openide.nodes], ModuleCL@8d5900a[org.netbeans.libs.scala.library], ModuleCL@41137b8e[org.netbeans.modules.java.project.ui], ModuleCL@13ed4b09[org.netbeans.libs.scalariform], ModuleCL@5d4ef27c[org.netbeans.modules.projectuiapi], ModuleCL@34942a0d[org.netbeans.api.templates], org.netbeans.MainImpl$BootClassLoader@238e0d81, ModuleCL@5db98db6[org.openide.io], ModuleCL@631100a4[org.netbeans.modules.maven], ...7 more]
   at org.netbeans.ProxyClassLoader.loadClass(ProxyClassLoader.java:224)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
Caused: java.lang.NoClassDefFoundError: org/netbeans/spi/project/ui/ProjectOpenedHook
   at java.lang.ClassLoader.defineClass1(ClassLoader.java:0)
   at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
   at org.netbeans.JarClassLoader.doLoadClass(JarClassLoader.java:311)
Caused: java.lang.NoClassDefFoundError: org/netbeans/spi/project/ui/ProjectOpenedHook while loading org.netbeans.modules.scala.maven.MavenProjectOpenedHook; see http://wiki.netbeans.org/DevFaqTroubleshootClassNotFound
   at org.netbeans.ProxyClassLoader.selfLoadClass(ProxyClassLoader.java:263)
   at org.netbeans.ProxyClassLoader.loadClass(ProxyClassLoader.java:187)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
   at org.netbeans.modules.scala.maven.MavenProjectOpenedHookLookupProvider.createAdditionalLookup(MavenProjectOpenedHookLookupProvider.java:29)
   at org.netbeans.spi.project.support.DelegatingLookupImpl.doDelegate(DelegatingLookupImpl.java:139)
   at org.netbeans.spi.project.support.DelegatingLookupImpl.access$100(DelegatingLookupImpl.java:63)
   at org.netbeans.spi.project.support.DelegatingLookupImpl$1.resultChanged(DelegatingLookupImpl.java:95)
   at sun.reflect.GeneratedMethodAccessor86.invoke(GeneratedMethodAccessor86.java:0)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   at java.lang.reflect.Method.invoke(Method.java:497)
   at org.openide.util.WeakListenerImpl$ProxyListener.invoke(WeakListenerImpl.java:487)
   at com.sun.proxy.$Proxy4.resultChanged(.java:0)
   at org.openide.util.lookup.AbstractLookup$NotifyListeners.run(AbstractLookup.java:542)
   at org.openide.loaders.FolderLookup$Dispatch.run(FolderLookup.java:314)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)