Ensure that Collections.isEmpty() is used to check if there are no
elements in a collections. This is more explicit and can be faster than
calling .size().
Closes gh-4783
Given that Spring Boot uses java config accross the board, a new `value`
attribute is now aliased to the existing `classes` attribute such that
one could write the following:
@SpringApplicationConfiguration(MyConfig.class)
public class MyTest {}
Closes gh-3635
Undertow’s WebSocket client sends an illegal Origin header – it does
not include the scheme, e.g. it’ll send “localhost” rather than
“http://localhost”. This commit works around the problem by allowing
access to the SockJS endpoints from any origin, thereby disabling
OriginHandlerInterceptor’s checking of the Origin header.
