Merge pull request #4033 from sebastienblanc/KEYCLOAK-3818

KEYCLOAK-3818 : safer method to retrieve the webcontext for jetty

adapters/oidc/spring-boot/src/main/java/org/keycloak/adapters/springboot/KeycloakSpringBootConfiguration.java

@@ -210,6 +210,10 @@ public class KeycloakSpringBootConfiguration {
             }
 
             WebAppContext webAppContext = server.getBean(WebAppContext.class);
+            //if not found as registered bean let's try the handler
+            if(webAppContext==null){
+                webAppContext = (WebAppContext) server.getHandler();
+            }
 
             ConstraintSecurityHandler securityHandler = new ConstraintSecurityHandler();
             securityHandler.setConstraintMappings(jettyConstraintMappings);