Found one Java-level deadlock:
=============================
"Default RequestProcessor":
  waiting to lock monitor 0x00000000410437b8 (object 0x00007f84fed03670, a java.lang.Class),
  which is held by "Opening projects"
"Opening projects":
  waiting to lock monitor 0x00000000411cbd18 (object 0x00007f850a9bce50, a org.netbeans.modules.project.ui.OpenProjectList$RecentProjectList),
  which is held by "Default RequestProcessor"

Java stack information for the threads listed above:
===================================================
"Default RequestProcessor":
	at org.netbeans.modules.project.ui.OpenProjectList.getDefault(OpenProjectList.java:227)
	- waiting to lock <0x00007f84fed03670> (a java.lang.Class for org.netbeans.modules.project.ui.OpenProjectList)
	at org.netbeans.modules.project.ui.actions.RecentProjects.propertyChange(RecentProjects.java:175)
	at org.openide.util.WeakListenerImpl$PropertyChange.propertyChange(WeakListenerImpl.java:196)
	at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
	at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
	at org.netbeans.modules.project.ui.OpenProjectList$RecentProjectList$1.run(OpenProjectList.java:1438)
	- locked <0x00007f850a9bce50> (a org.netbeans.modules.project.ui.OpenProjectList$RecentProjectList)
	at org.openide.util.Mutex.readAccess(Mutex.java:365)
	at org.netbeans.modules.project.ui.OpenProjectList$RecentProjectList.refresh(OpenProjectList.java:1401)
	at org.netbeans.modules.project.ui.OpenProjectList$NbProjectDeletionListener.fileDeleted(OpenProjectList.java:1698)
	at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEventImpl(FCLSupport.java:148)
	at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEvent(FCLSupport.java:128)
	at org.openide.filesystems.FCLSupport.dispatchEvent(FCLSupport.java:105)
	at org.openide.filesystems.FileObject$ED.dispatch(FileObject.java:1123)
	at org.openide.filesystems.FileSystem$EventDispatcher.run(FileSystem.java:943)
	at org.openide.filesystems.EventControl.dispatchEvent(EventControl.java:82)
	at org.openide.filesystems.FileSystem.dispatchEvent(FileSystem.java:601)
	at org.openide.filesystems.FileObject.dispatchEvent(FileObject.java:532)
	at org.openide.filesystems.FileObject.fireFileDeletedEvent(FileObject.java:508)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.fireFileDeletedEvent(BaseFileObj.java:637)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.FolderObj.delete(FolderObj.java:351)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj$2.call(BaseFileObj.java:684)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj$2.call(BaseFileObj.java:679)
	at org.netbeans.modules.masterfs.filebasedfs.FileBasedFileSystem.runAsInconsistent(FileBasedFileSystem.java:115)
	at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.delete(BaseFileObj.java:693)
	at org.openide.filesystems.FileObject.delete(FileObject.java:366)
	at org.netbeans.modules.project.uiapi.DefaultProjectOperationsImplementation.performDelete(DefaultProjectOperationsImplementation.java:139)
	at org.netbeans.modules.project.uiapi.DefaultProjectOperationsImplementation.access$200(DefaultProjectOperationsImplementation.java:102)
	at org.netbeans.modules.project.uiapi.DefaultProjectOperationsImplementation$1.execute(DefaultProjectOperationsImplementation.java:205)
	at org.netbeans.modules.project.uiapi.DefaultProjectOperationsImplementation$6$1.run(DefaultProjectOperationsImplementation.java:641)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1418)
	at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1960)
"Opening projects":
	at org.netbeans.modules.project.ui.OpenProjectList$RecentProjectList.getRecentProjectsInfo(OpenProjectList.java:1567)
	- waiting to lock <0x00007f850a9bce50> (a org.netbeans.modules.project.ui.OpenProjectList$RecentProjectList)
	at org.netbeans.modules.project.ui.OpenProjectList$RecentProjectList.access$1600(OpenProjectList.java:1336)
	at org.netbeans.modules.project.ui.OpenProjectList$8.run(OpenProjectList.java:955)
	- locked <0x00007f84fed03670> (a java.lang.Class for org.netbeans.modules.project.ui.OpenProjectList)
	at org.netbeans.modules.project.ui.OpenProjectList$8.run(OpenProjectList.java:952)
	at org.openide.util.Mutex.readAccess(Mutex.java:288)
	at org.netbeans.modules.project.ui.OpenProjectList.getRecentProjectsInformation(OpenProjectList.java:952)
	at org.netbeans.modules.project.ui.api.RecentProjects.getRecentProjectInformation(RecentProjects.java:99)
	at org.netbeans.modules.welcome.content.RecentProjectsPanel.rebuildContent(RecentProjectsPanel.java:122)
	at org.netbeans.modules.welcome.content.RecentProjectsPanel.access$000(RecentProjectsPanel.java:75)
	at org.netbeans.modules.welcome.content.RecentProjectsPanel$1.propertyChange(RecentProjectsPanel.java:107)
	at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
	at org.netbeans.modules.project.ui.api.RecentProjects$1.propertyChange(RecentProjects.java:84)
	at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
	at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
	at org.netbeans.modules.project.ui.OpenProjectList.close(OpenProjectList.java:831)
	at org.netbeans.modules.project.ui.actions.CloseProject.actionPerformed(CloseProject.java:85)
	at org.netbeans.modules.project.ui.actions.CloseProject$1.run(CloseProject.java:78)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1418)
	at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1960)

Found 1 deadlock.