Sometimes (probably once or twice a month) my eclipse freezes either right at startup or short after startup if I try to save some modified file. In Java VisualVM I can see than a deadlock in org.jboss.ide.eclipse.as.core.JBossServerCorePlugin.start() method.
Today I have updated JBoss plugins to latest version (from the update site for JBoss Tools 4.2.2.Final) and was able to reproduce the problem at every second or third startup . It looks like it occurs on larger workspaces (my current workspace has about 70 open projects (most of them are java projects and depends on each other)) and if servers view is open/visible right at startup. In a smaller workspace with only 11 projects I had no luck reproducing the deadlock.