Race condition

[dtbaum]

When the first GET request is in progress, all parallel requests from other Jersey clients, in other threads, fail with SSLHandshakeException: PKIX path building failed.
Once the first GET request is completed, all subsequent requests work without error.
Here is the code which demonstrates this issue:
https://github.com/dtbaum/jersey-bug-report

The fix in HttpUrlConnector.java solved the issue, see pull request #5359.
Affected versions: at least 3.1.2 & OpenJDK17 and 2.37 & OpenJDK 8

[fwippe]

@senivam @jansupol @dtbaum Please note that this change has been having a drastic impact on performance, in particular when using Jersey client for multiple services: Only one connection can be created at a time, across all routes. If the intention had been to just synchronize HttpsURLConnection.getDefaultSSLSocketFactory(), as an alternative you could have introduced a lazy one-off supplier initializing the socket factory. What do you think?

See #5738 for performance impact in practice.