Some thoughts and review

[aliaksei-lithium]

• Try to use kotlin-spring to eliminate open keyword usage. Checkout here https://blog.jetbrains.com/kotlin/2016/12/kotlin-1-0-6-is-here/
• Rewrite if logic in ForwardFilter to simplify understanding. Like:

          if (uri.startsWithIC(arrayOf("/ui", "/ui/js", "/ui/css")) {}

• Remove @Autowired from constructor DI (e.g. FooController)
• For logging, check nice delegate

  // usage
      companion object {
          private val log by logger()
      }   
  // definition
      fun <R : Any> R.logger(): Lazy<Logger> {
          return lazy { LoggerFactory.getLogger(unwrapCompanionClass(this.javaClass).name) }
      }

  private fun <T: Any> unwrapCompanionClass(ofClass: Class<T>): Class<*> {
  return if (ofClass.enclosingClass != null && ofClass.enclosingClass.kotlin.companionObject?.java == ofClass) {
      ofClass.enclosingClass
  } else {
      ofClass
  }
  }

• icu4j - Big lib fo such small usage?
• in Foo

  val message: String
          get() = rule.format(value)

  can be replaced to lazy delegate. Object is immutable, no needs to format each time

• No need @Autowired with @Bean annotations(check config.oauth package)
• Try to find another way to deal with null's in such cases SettingsUserDetailsService settings.users.find {it.user == username}!!
• OAuth2ErrorController not sure how it will work with clients w/o UI, just "rest" clients?

[barlog-m]

Thank you very much for code review. I fixed most of this.