Ignite newcomers tend to stumble on deadlocks simply because the keys are passed in an unordered HashMap. Propose to do the following:
- update bulk operations Java docs.
- print out a warning if not SortedMap (e.g. HashMap, Weak/Identity/Concurrent/Linked HashMap etc) is passed into
a bulk method (instead of SortedMap) and contains more than 1 element. However, we should make sure that we only print that warning once and not every time the API is called.
- do not produce warning for explicit optimistic transactions