Program: 62374
Project: 62374
Buggy source:
public void registerWatcher(Path path){
  threadService.runTaskLater(() -> {
    try {
      if (Objects.isNull(watcher)) {
        watcher=FileSystems.getDefault().newWatchService();
      }
      if (!path.equals(lastWatchedPath)) {
        if (Objects.nonNull(lastWatchKey)) {
          lastWatchKey.cancel();
        }
        lastWatchedPath=path;
        this.lastWatchKey=path.register(watcher,ENTRY_CREATE,ENTRY_DELETE,ENTRY_MODIFY);
      }
      logger.debug("String_Node_Str",path);
      while (true) {
        if (!lastWatchKey.isValid())         break;
        this.watckKey=watcher.take();
        List<WatchEvent<?>> watchEvents=watckKey.pollEvents();
        boolean updateFsView=false;
        for (        WatchEvent<?> event : watchEvents) {
          WatchEvent.Kind<?> kind=event.kind();
          if (kind == ENTRY_MODIFY && event.count() == 1) {
            WatchEvent<Path> ev=(WatchEvent<Path>)event;
            Path modifiedPath=path.resolve(ev.context());
            threadService.runActionLater(() -> {
              ObservableList<Tab> tabs=controller.getTabPane().getTabs();
              for (              Tab tab : tabs) {
                MyTab myTab=(MyTab)tab;
                if (modifiedPath.equals(myTab.getPath())) {
                  myTab.askReloadDocument("String_Node_Str");
                  break;
                }
              }
              watckKey.reset();
            }
);
          }
 else           if (kind == ENTRY_MODIFY && event.count() > 1) {
            watckKey.reset();
          }
 else {
            updateFsView=true;
            watckKey.reset();
          }
        }
        if (updateFsView) {
          fileBrowseService.browse(lastWatchedPath);
        }
      }
    }
 catch (    ClosedWatchServiceException e) {
      logger.debug("String_Node_Str",path,e);
    }
catch (    Exception e) {
      logger.debug("String_Node_Str",path,e);
    }
  }
);
}

Fixed version (ground truth):
public void registerWatcher(Path path){
  threadService.runTaskLater(() -> {
    try {
      if (Objects.isNull(watcher)) {
        watcher=FileSystems.getDefault().newWatchService();
      }
      if (!path.equals(lastWatchedPath)) {
        if (Objects.nonNull(lastWatchKey)) {
          lastWatchKey.cancel();
          watcher.close();
          watcher=FileSystems.getDefault().newWatchService();
        }
        lastWatchedPath=path;
        this.lastWatchKey=path.register(watcher,ENTRY_CREATE,ENTRY_DELETE,ENTRY_MODIFY);
      }
      logger.debug("String_Node_Str",path);
      while (true) {
        if (!lastWatchKey.isValid())         break;
        this.watckKey=watcher.take();
        List<WatchEvent<?>> watchEvents=watckKey.pollEvents();
        boolean updateFsView=false;
        for (        WatchEvent<?> event : watchEvents) {
          WatchEvent.Kind<?> kind=event.kind();
          if (kind == ENTRY_MODIFY && event.count() == 1) {
            WatchEvent<Path> ev=(WatchEvent<Path>)event;
            Path modifiedPath=path.resolve(ev.context());
            threadService.runActionLater(() -> {
              ObservableList<Tab> tabs=controller.getTabPane().getTabs();
              for (              Tab tab : tabs) {
                MyTab myTab=(MyTab)tab;
                if (modifiedPath.equals(myTab.getPath())) {
                  myTab.askReloadDocument("String_Node_Str");
                  break;
                }
              }
              watckKey.reset();
            }
);
          }
 else           if (kind == ENTRY_MODIFY && event.count() > 1) {
            watckKey.reset();
          }
 else {
            updateFsView=true;
            watckKey.reset();
          }
        }
        if (updateFsView) {
          fileBrowseService.browse(lastWatchedPath);
        }
      }
    }
 catch (    ClosedWatchServiceException e) {
      logger.debug("String_Node_Str",path,e);
    }
catch (    Exception e) {
      logger.debug("String_Node_Str",path,e);
    }
  }
);
}