RFR: 8293630: Simplify TreeMap.get() with Comparator.naturalOrder()

[liach]

On Wed, 17 Aug 2022 11:23:57 GMT, Сергей Цыпанов <duke at openjdk.org> wrote:

> We can use `Comparator.naturalOrder()` for cases when a `TreeMap` instance is constructed without comparator. This allows to squash two branches in `TreeMap.get()` into one.
> 
> P.S. I think the comment of `TreeMap.getEntryUsingComparator()` is outdated. Should we also change it?

src/java.base/share/classes/java/util/TreeMap.java line 3318:

> 3316:             // Adapt or create a key-based comparator
> 3317:             Comparator<? super K> treeComparator = tree.comparator;
> 3318:             return Map.Entry.comparingByKey(treeComparator == null ? natural() : treeComparator);

You can probably have:

return treeComparator == nul ?
        Map.Entry.comparingByKey() :
        Map.Entry.comparingByKey(treeComparator);

instead.

-------------

PR: https://git.openjdk.org/jdk/pull/9901