On Sun, 27 Jun 2021 12:45:35 GMT, Marius Hanl <mh...@openjdk.org> wrote:
>> Without the check, it would be possible to inspect the size without calling >> `next()` first. > > Right. But I want to understand why this was not there before. > > Is this needed, because if you didn't called `next()`, there is no change yet > to retrieve the removed size? It is needed according to the documentation of `ListChangeListener.Change`: _Important: It's necessary to call next() method before calling any other method of Change. The same applies after calling reset(). The only methods that works at any time is getList()._ Also, it intuitively makes sense: a `Change` can consist of any number of sub-changes, so you need to select a sub-change first by calling `next()` before any of the other methods can be meaningfully called. ------------- PR: https://git.openjdk.java.net/jfx/pull/478
