On 20/11/2018 17:55, Seán Coffey wrote:
A race condition recently reported by the WLS team. Access to the
handlers Hashtable and the factory should be made while holding the
streamHandlerLock lock.
WLS team also made efforts to create a reproducer. I've modified to
jtreg format and reduced it down further for unit testing.
https://bugs.openjdk.java.net/browse/JDK-8213942
webrev: http://cr.openjdk.java.net/~coffeys/webrev.8213942/webrev/
Most URLs are created without specifying a handler so it means creating
a URL will go through getURLStreamHandler most of the time. So I think
we want to avoid locking on that code path where possible. It's sad that
handlers is a Hashtable but I think it makes it worse to have it always
synchronize on streamHandlerLock. Reading this code makes me want to
replace handlers and replace it with fully concurrent lookups but I
realize you might not want to go there for this issue (as I assume you
are looking to back-port it). Assuming you don't want a re-write, have
you considered always retrying handles.get(protocol) when you acquire
the lock?
-Alan
