fix checkstyle

src/main/java/eu/europa/ec/dgc/validation/decorator/controller/CallbackController.java

@@ -53,7 +53,8 @@ public class CallbackController {
      * 
      * @param subject Subject
      */
-    @Operation(summary = "The optional callback endpoint receives the validation result to a subject", description = "The optional callback endpoint receives the validation result to a subject")
+    @Operation(summary = "The optional callback endpoint receives the validation result to a subject", 
+            description = "The optional callback endpoint receives the validation result to a subject")
     @ApiResponses(value = {
         @ApiResponse(responseCode = "200", description = "OK"),
         @ApiResponse(responseCode = "401", description = "Unauthorized, if Result Token was not correctly signed"),

src/main/java/eu/europa/ec/dgc/validation/decorator/service/SubjectService.java

@@ -1,3 +1,4 @@
+
 package eu.europa.ec.dgc.validation.decorator.service;
 
 import eu.europa.ec.dgc.validation.decorator.config.DgcProperties.ServiceProperties;
@@ -20,9 +21,15 @@
 public class SubjectService {
 
     private final IdentityService identityService;
-    
+
     private final BackendRepository backendRepository;
-
+
+    /**
+     * Determines the service based on the subject.
+     * 
+     * @param subject Sibject ID
+     * @return {@link ServiceProperties}
+     */
     public ServiceProperties getServiceBySubject(String subject) {
         final ServiceTokenContentResponse tokenContent = this.getBackendTokenContent(subject);
         if (tokenContent != null && tokenContent.getSubjects() == null || tokenContent.getSubjects().isEmpty()) {
@@ -36,15 +43,15 @@ public ServiceProperties getServiceBySubject(String subject) {
             throw new DccException(String.format("Subject without service ID '%s'", serviceId),
                     HttpStatus.NO_CONTENT.value());
         }
-        
+
         final String decodedServiceId = new String(Base64.getUrlDecoder().decode(serviceId), StandardCharsets.UTF_8);
         log.debug("Receive service ID (decoded) from booking service '{}'", decodedServiceId);
 
         final ServiceProperties service = this.identityService.getServicePropertiesById(decodedServiceId);
         log.debug("Receive service: {}", service);
         return service;
     }
-    
+
     private ServiceTokenContentResponse getBackendTokenContent(final String subject) {
         try {
             return this.backendRepository.tokenContent(subject);