diff --git a/app/controllers/iop/collaboration/impl/CollaborativeExamController.java b/app/controllers/iop/collaboration/impl/CollaborativeExamController.java
index ca183ad41..6e198d63f 100644
--- a/app/controllers/iop/collaboration/impl/CollaborativeExamController.java
+++ b/app/controllers/iop/collaboration/impl/CollaborativeExamController.java
@@ -100,7 +100,7 @@ private Exam prepareDraft(User user) {
 
     @Authenticated
     @Restrict({ @Group("ADMIN"), @Group("TEACHER") })
-    public CompletionStage<Result> searchExams(Http.Request request, final Optional<String> filter) {
+    public CompletionStage<Result> searchExams(Http.Request request, Optional<String> filter) {
         WSRequest wsRequest = getSearchRequest(filter);
         User user = request.attrs().get(Attrs.AUTHENTICATED_USER);
         String homeOrg = configReader.getHomeOrganisationRef();
diff --git a/ui/src/app/enrolment/enrolment.service.ts b/ui/src/app/enrolment/enrolment.service.ts
index 0c9043ff7..22165d8df 100644
--- a/ui/src/app/enrolment/enrolment.service.ts
+++ b/ui/src/app/enrolment/enrolment.service.ts
@@ -188,7 +188,7 @@ export class EnrolmentService {
         this.http.get<CollaborativeParticipation[]>('/app/iop/student/finishedExams');
 
     searchExams$ = (searchTerm: string): Observable<CollaborativeExam[]> => {
-        const paramStr = '?filter=' + (searchTerm?.length > 0 ? encodeURIComponent(searchTerm) : '');
+      const paramStr = searchTerm ? `?filter=${encodeURIComponent(searchTerm)}` : '';
         const path = `/app/iop/enrolment${paramStr}`;
         return this.http.get<CollaborativeExam[]>(path);
     };
diff --git a/ui/src/app/exam/collaborative/collaborative-exam.service.ts b/ui/src/app/exam/collaborative/collaborative-exam.service.ts
index e84c19595..5582c017b 100644
--- a/ui/src/app/exam/collaborative/collaborative-exam.service.ts
+++ b/ui/src/app/exam/collaborative/collaborative-exam.service.ts
@@ -44,7 +44,7 @@ export class CollaborativeExamService {
     createExam$ = (): Observable<CollaborativeExam> => this.http.post<CollaborativeExam>('/app/iop/exams', {});
 
     searchExams$ = (searchTerm: string): Observable<CollaborativeExam[]> => {
-        const paramStr = '?filter=' + (searchTerm && searchTerm.length > 0 ? encodeURIComponent(searchTerm) : '');
+        const paramStr = searchTerm ? `?filter=${encodeURIComponent(searchTerm)}` : '';
         const path = `/app/iop/exams${paramStr}`;
         return this.http.get<CollaborativeExam[]>(path);
     };