Polish OAuth2ClientConfiguration

[kse-music]

Use constructor inject and use ObjectProvider.getIfUnique instead of list.size == 1

[jzheaux]

Thanks for the cleanup, @kse-music! Will you please add some more detail to your Git commit so that it is clear from reading the title what is going on? In the absence of a ticket that already has this detail, it would also be helpful if the commit had a description as to the benefit of this commit.

Second, I imagine that this pattern of taking a list and checking the size is common in Spring Security. Can you update the PR to clean up other places as well (e.g. OAuth2ClientConfiguration, AbstractSecurityWebSocketMessageBrokerConfigurer, etc.).

Finally, I think it would be better to do the Arrays.asList -> Collections.singleton maneuver in a separate PR since there are likely many places where this appears as well.

I can help with additional commits for anything you feel you don't have time for, just let me know.

[kse-music]

@jzheaux After inspection, only OAuth2ClientConfiguration, OAuth2ClientWebFluxSecurityConfiguration, and AbstractSecurityWebSocketMessageBrokerConfigurer were found to have the only bean judgment in the spring-config module. All except AbstractSecurityWebSocketMessageBrokerConfigurer have been modified because it tag deprecated.

If I have overlooked anything or other needs to be revised, please feel free to add it.

[rwinch]

Finally, I think it would be better to do the Arrays.asList -> Collections.singleton maneuver in a separate PR since there are likely many places where this appears as well.

Note that Arrays.asList is mutable and Collections.singleton is not. Switching to an immutable Collection would be considered as a breaking change.

[jzheaux]

@rwinch, I learned something new today. :) I had always thought Arrays.asList was immutable since I couldn't add or remove from it. However, you can use set(index, value). Good catch.