simplify UnitOfWork code

commafeed-server/src/main/java/com/commafeed/backend/dao/UnitOfWork.java

@@ -1,5 +1,7 @@
 package com.commafeed.backend.dao;
 
+import java.util.concurrent.Callable;
+
 import jakarta.inject.Singleton;
 
 import io.quarkus.narayana.jta.QuarkusTransaction;
@@ -7,25 +9,11 @@ import io.quarkus.narayana.jta.QuarkusTransaction;
 @Singleton
 public class UnitOfWork {
 
-	public void run(SessionRunner runner) {
+	public void run(Runnable runnable) {
-		call(() -> {
+		QuarkusTransaction.joiningExisting().run(runnable);
-			runner.runInSession();
-			return null;
-		});
 	}
 
-	public <T> T call(SessionRunnerReturningValue<T> runner) {
+	public <T> T call(Callable<T> callable) {
-		return QuarkusTransaction.joiningExisting().call(runner::runInSession);
+		return QuarkusTransaction.joiningExisting().call(callable);
 	}
-
-	@FunctionalInterface
-	public interface SessionRunner {
-		void runInSession();
-	}
-
-	@FunctionalInterface
-	public interface SessionRunnerReturningValue<T> {
-		T runInSession();
-	}
-
 }