Refactor SSLSocket and JSSSocket

[edewata]

SSLSocket is an older code based on the plain Java Socket. JSSSocket is a newer code based on Java SSLEngine and should eventually replace SSLSocket.

To help the transition, SSLSocket has been modified to extend javax.net.ssl.SSLSocket and JSSSocket has been modified to extend SSLSocket. Once everything is migrated to JSSSocket, the SSLSocket can be deprecated and eventually dropped.

https://github.com/edewata/jss/blob/socket/docs/changes/v5.6.0/API-Changes.adoc

[sonarqubecloud]

Quality Gate failed

Failed conditions
B Maintainability Rating on New Code (required ≥ A)

See analysis details on SonarCloud

Catch issues before they fail your Quality Gate with our IDE extension SonarLint

[fmarco76]

The change for SSLSocket looks good to me. I have a concern for the JSSSocket but I am OK either way.

Since there is an alternative, could we add the deprecated now in SSLSocket?

[fmarco76]

If the goal is to deprecate/remove SSLSocket it is not clear to me the reason of this change.

[edewata]

This is needed to simplify the transition by minimizing the required changes to existing code. Basically any code that creates the old SSLSocket can be changed to create JSSSocket instead, but the code that uses the SSLSocket instance can automatically use the JSSSocket instance without any changes since it's a subclass, and JSSSocket will inherit the constants defined in SSLSocket too.

[fmarco76]

The changes will be needed in order to remove SSLSocket but we can do later.

[edewata]

@fmarco76 Thanks! I'll merge it now but feel free to continue the discussion.

About deprecation, if we add it now it will just generate more warnings during the build. I'd rather we add it later once we migrate all of our code (i.e. in jss itself, ldapjdk and pki) to use JSSSocket and making sure that it can fully replace the old SSLSocket.