On Fri, 29 Mar 2024 20:02:53 GMT, Alexey Ivanov <aiva...@openjdk.org> wrote:
>>> However, there are cases where instantiating and testing is safe on main >>> thread. >> >> That is my point, make it less safe - when the component is created on one >> thread:EDT and then for some reason accessed on a different thread, the >> rescanCurrentDirectory should still work. > >> > However, there are cases where instantiating and testing is safe on main >> > thread. >> >> That is my point, make it less safe - when the component is created on one >> thread:EDT and then for some reason accessed on a different thread, the >> rescanCurrentDirectory should still work. > > I got your idea! > > However, I still see no benefit for doing it. > > Yes, when `JFileChooser` is instantiated, it creates its UI delegates and the > default model, `BasicDirectoryModel`. The constructor of the model calls > `validateFileCache` which starts the background thread and will update > `fileCache`. > > It does not make the initialisation less thread-safe: the same two threads > are involved — `FilesLoader` and EDT. Yet there's no race yet… > > The `ConcurrentModificationException` is thrown when the background > `FilesLoader` is iterating over `fileCache` while EDT runs > `DoChangeContents.run` which adds elements to `fileCache` or removes elements > from it. > > By the time the `Scanner` threads start, a race becomes possible. If the > initial `FilesLoader` completes and posts the `DoChangeContents` object to > EDT, the `FilesLoader` threads created by the scanners will race… but > `fileCache` is empty initially, thus iterating over it is very quick. > > Therefore getting `ConcurrentModificationException` is unlikely until > `fileCache` contains a list of files. This state is reached later in the > timeline of the test. > > The initial `FilesLoader` thread that's started when `JFileChooser` is > instantiated plays a role too… Yet it's running concurrently with the > `Scanner` threads whether the `JFileChooser` object is created on the current > thread or on EDT. > > --- > > Taking the above into account, instantiating `JFileChooser` on EDT adds > complexity to the test but brings no benefits. ok, I agree with you. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18109#discussion_r1545858033
