I have also tried openjdk-9 and oracle's Java 8 update 64 (built using java-package), but crashes were still happening - so maybe it is not related to java, as I thought initially.
I have now downgraded to xserver 1:7.7+12. Seems stable so far. I'll send another update if this one also crashes... B. this freemail appends ads, sorry: -- реклама ----------------------------------------------------------- Поторопись зарегистрировать самый короткий почтовый адрес @i.ua http://mail.i.ua/reg - и получи 1Gb для хранения писем