HashMap resize method implementation detail

Question

As the title suggests this is a question about an implementation detail from HashMap#resize - that\'s when the inner array is doubled in size. It\'s a bit word

Answer 1

The design consideration has been documented within the same source file, in a code comment in line 211

* When bin lists are treeified, split, or untreeified, we keep 
* them in the same relative access/traversal order (i.e., field 
* Node.next) to better preserve locality, and to slightly 
* simplify handling of splits and traversals that invoke 
* iterator.remove. When using comparators on insertion, to keep a 
* total ordering (or as close as is required here) across 
* rebalancings, we compare classes and identityHashCodes as 
* tie-breakers. 

Since removing mappings via an iterator can’t trigger a resize, the reasons to retain the order specifically in resize are “to better preserve locality, and to slightly simplify handling of splits”, as well as being consistent regarding the policy.