Mapstruct doesn't generate the mapping code

Why isn't my MapStruct mapper populating my entity objects correctly?

I believe I'm doing everything correctly, but for some reason, the mapping doesn't seem to work. Here are the details of my setup:

• Mapper Interface:

  @Mapper(
      componentModel = "spring",
      unmappedTargetPolicy = ReportingPolicy.IGNORE,
      unmappedSourcePolicy = ReportingPolicy.IGNORE
  )
  public interface UserTaskMapper {
      UserTask toEntity(UserTaskRequest userTaskRequest);
      UserTaskResponse toResponse(UserTask userTask);
  }
  

• Entity Class:

  @Entity
  @Getter
  @Setter
  @RequiredArgsConstructor
  @Table(name = "user_tasks")
  public class UserTask {
  
      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      private Long id;
  
      @ManyToOne
      @JoinColumn(name = "user_id", nullable = false)
      private User user;
  
      @ManyToOne
      @JoinColumn(name = "task_id", nullable = false)
      private Task task;
  
      private Boolean isCompleted;
      private String projectUrl;
      private LocalDateTime submittedAt;
  }
  

• Request DTO:

  @Getter
  @Setter
  public class UserTaskRequest {
      private Long taskId;
      private Set<Long> userIds;
      private Boolean isCompleted = false;
      private String projectUrl;
  }
  

• Response DTO:

  @Getter
  @Setter
  public class UserTaskResponse {
      private Long id;
      private Long userId;
      private TaskResponse task;
      private Boolean isCompleted;
      private String projectUrl;
      private LocalDateTime submittedAt;
  }
  

• Generated Mapper Implementation:

  @Generated(
      value = "org.mapstruct.ap.MappingProcessor",
      date = "2025-05-03T19:59:56+0400",
      comments = "version: 1.6.3, compiler: IncrementalProcessingEnvironment from gradle-language-java-8.13.jar, environment: Java 17.0.14 (Amazon.com Inc.)"
  )
  @Component
  public class UserTaskMapperImpl implements UserTaskMapper {
  
      @Override
      public UserTask toEntity(UserTaskRequest userTaskRequest) {
          if (userTaskRequest == null) {
              return null;
          }
          UserTask userTask = new UserTask();
          return userTask;
      }
  
      @Override
      public UserTaskResponse toResponse(UserTask userTask) {
          if (userTask == null) {
              return null;
          }
          UserTaskResponse userTaskResponse = new UserTaskResponse();
          return userTaskResponse;
      }
  }
  

Here, the generated mapper is just returning empty objects without mapping any fields.

I've tried several fixes:

1. Cleaning and rebuilding the project multiple times.
2. Updating dependencies—I changed:

   implementation 'org.mapstruct:mapstruct:1.6.3'
   annotationProcessor 'org.mapstruct:mapstruct-processor:1.6.3'
   

   from version 1.5.5.Final. But this didn't resolve the issue.

Despite these efforts, the mapping still isn't working correctly. How can I fix this?