diff --git a/src/main/java/de/szut/lf8_starter/exceptionHandling/GlobalExceptionHandler.java b/src/main/java/de/szut/lf8_starter/exceptionHandling/GlobalExceptionHandler.java
index 68a15a7..8ee2aaf 100644
--- a/src/main/java/de/szut/lf8_starter/exceptionHandling/GlobalExceptionHandler.java
+++ b/src/main/java/de/szut/lf8_starter/exceptionHandling/GlobalExceptionHandler.java
@@ -21,7 +21,7 @@ import java.util.Date;
 public class GlobalExceptionHandler {
 
     @ExceptionHandler(ResourceNotFoundException.class)
-    public ResponseEntity<?> handleHelloEntityNotFoundException(ResourceNotFoundException ex, WebRequest request) {
+    public ResponseEntity<ErrorDetails> handleHelloEntityNotFoundException(ResourceNotFoundException ex, WebRequest request) {
         ErrorDetails errorDetails = new ErrorDetails(new Date(), ex.getMessage(), request.getDescription(false));
         return new ResponseEntity<>(errorDetails, HttpStatus.NOT_FOUND);
     }
diff --git a/src/main/java/de/szut/lf8_starter/security/KeycloakSecurityConfig.java b/src/main/java/de/szut/lf8_starter/security/KeycloakSecurityConfig.java
index 8ab3fd8..7ff32cc 100644
--- a/src/main/java/de/szut/lf8_starter/security/KeycloakSecurityConfig.java
+++ b/src/main/java/de/szut/lf8_starter/security/KeycloakSecurityConfig.java
@@ -83,9 +83,9 @@ class KeycloakSecurityConfig {
         jwtAuthenticationConverter.setJwtGrantedAuthoritiesConverter(jwt -> {
             List<GrantedAuthority> grantedAuthorities = new ArrayList<>();
 
-            Map<String, Object> realmAccess = jwt.getClaim("realm_access");
-            if (realmAccess != null && realmAccess.containsKey("roles")) {
-                List<String> roles = (List<String>) realmAccess.get("roles");
+            Map<String, Object> realmAccess = jwt.getClaim(REALM_ACCESS_CLAIM);
+            if (realmAccess != null && realmAccess.containsKey(ROLES_CLAIM)) {
+                List<String> roles = (List<String>) realmAccess.get(ROLES_CLAIM);
                 for (String role : roles) {
                     grantedAuthorities.add(new SimpleGrantedAuthority("ROLE_" + role));
                 }
diff --git a/src/main/java/de/szut/lf8_starter/welcome/WelcomeController.java b/src/main/java/de/szut/lf8_starter/welcome/WelcomeController.java
index 6ed067b..4effa6b 100644
--- a/src/main/java/de/szut/lf8_starter/welcome/WelcomeController.java
+++ b/src/main/java/de/szut/lf8_starter/welcome/WelcomeController.java
@@ -1,14 +1,12 @@
 package de.szut.lf8_starter.welcome;
 
-
-
 import org.springframework.http.ResponseEntity;
-import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.security.core.Authentication;
+import org.springframework.security.core.GrantedAuthority;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import java.security.Principal;
+import java.util.Collection;
 
 @RestController
 public class WelcomeController {
@@ -19,8 +17,8 @@ public class WelcomeController {
     }
 
     @GetMapping("/roles")
-    public ResponseEntity<?> getRoles(Authentication authentication) {
-        return ResponseEntity.ok(authentication.getAuthorities());
+    public ResponseEntity<Collection<GrantedAuthority>> getRoles(Authentication authentication) {
+        return ResponseEntity.ok((Collection<GrantedAuthority>) authentication.getAuthorities());
     }