I dont have exact steps to reproduce because this usually occurs after longer work. I'm testing various configurators (CDI/Seam/JAXRS..) using this scenario:
1. Create Dynamic Web Project
2. Convert to maven project (using Configure -> Convert to maven..)
3. Add some dependency
4. check if proper facet was enabled
5. delete project and repeat

After trying this 10-15 times (sometimes more, sometimes less), during step 2 "Enabling Maven Dependency Management" job is waiting and never ends - see screenshot - there's always "Setting classpath containers".

JVM thread dump attached.