What I want to talk about though is a way to solve this problem. Quit a simple way - just force an order on your transaction writes and you're guaranteed not to deadlock: if both T1 and T2 write to a then b (lexicographical order) there won't be any deadlock. Ever.
But there's a catch. It's not always possible to define this order, simply because you can't or because you don't know all your keys at the very beginning of the transaction.
Now here's the good news: Infinispan orders the keys touched in a transaction for you. And it even defines an order so that you won't have to do that. Actually you don't have to anything, not even enable this feature, as it is already enabled for you by default.
Does it sound too good to be true? That's because it's only partially true. That is lock reordering only works if you're using optimistic locking. For pessimistic locking you still have to do it the old way - order your locks (that's of course if you can).
Wanna know more about it? Read this.
Expect and enjoy this feature in our next release 5.1.0.BETA5.