package hello;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import org.thymeleaf.spring.support.ThymeleafLayoutInterceptor;

@Configuration
public class WebMvcConfig extends WebMvcConfigurationSupport {
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new ThymeleafLayoutInterceptor());
    }
}

@@ -219,28 +219,25 @@
 Configur
-ationSupport
+erAdapter
 ;%0Aimport
@@ -362,23 +362,21 @@
 igur
-ationSupport
+erAdapter
  %7B%0A
+%0A
     
@@ -394,16 +394,13 @@
    p
-rotected
+ublic
  voi

Extend from WebMvcConfigurerAdapter instead so that @AuthenticationPrincipal will work.