Created attachment 199589 [details]
java runtime disappeared

LibreOffice lagged when the preferences window was opened, especially when the "Advanced" pane was clicked. 

In the "Advanced" pane, I found that the usual Java runtime in the list box had disappeared. I was not able to click anything since then. Even when I clicked something, its response was extremely delayed to the extent that I could not do anything in the preferences window but close it by hitting the "escape" button on the keyboard. Sometimes, the problem was so severe that the preferences window could not be closed, and I needed to force-kill the program. 

While checking from the "Activity Monitor" on Mac, I found that the program's memory usage was quite high, sometimes up to 7xxM. Still, the program did not open any document except the preferences window.