I'm getting a lot of those lately (Java.long.pointer.exception.blahblah). Like five today and three yesterday. Sometimes when I press send, or even selecting a piece to move.
Is it my computer? Or does that mean LG is instable?
The Java NullPointerException is on the server, not on your computer or in your browser. One reason that the Exceptions in production are intermittent is that the ones that are consistent are caught in testing.
When I get NullPointerException making a move (and it's When, not If), the move's URL remains in the address bar, and it works when resubmitted, which is faster than redisplaying the game and making the move from scratch. (More so in Wyps, which always has multi-part moves, than in Hex, which always has one-step moves)