diff --git a/src/main/java/cc/ryanc/halo/service/base/AbstractCrudService.java b/src/main/java/cc/ryanc/halo/service/base/AbstractCrudService.java
index 7a5f8866b..42076339e 100644
--- a/src/main/java/cc/ryanc/halo/service/base/AbstractCrudService.java
+++ b/src/main/java/cc/ryanc/halo/service/base/AbstractCrudService.java
@@ -96,7 +96,7 @@ public abstract class AbstractCrudService<DOMAIN, ID> implements CrudService<DOM
     }
 
     @Override
-    public DOMAIN getNullableById(ID id) {
+    public DOMAIN getByIdOfNullable(ID id) {
         return fetchById(id).orElse(null);
     }
 
diff --git a/src/main/java/cc/ryanc/halo/service/base/CrudService.java b/src/main/java/cc/ryanc/halo/service/base/CrudService.java
index 0850afbc7..fb1d2f1a5 100644
--- a/src/main/java/cc/ryanc/halo/service/base/CrudService.java
+++ b/src/main/java/cc/ryanc/halo/service/base/CrudService.java
@@ -1,5 +1,6 @@
 package cc.ryanc.halo.service.base;
 
+import cc.ryanc.halo.exception.NotFoundException;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
@@ -15,7 +16,6 @@ import java.util.Optional;
  *
  * @param <DOMAIN> domain type
  * @param <ID>     id type
- *
  * @author johnniang
  */
 public interface CrudService<DOMAIN, ID> {
@@ -33,7 +33,6 @@ public interface CrudService<DOMAIN, ID> {
      * List all by sort
      *
      * @param sort sort
-     *
      * @return List
      */
     @NonNull
@@ -43,7 +42,6 @@ public interface CrudService<DOMAIN, ID> {
      * List all by pageable
      *
      * @param pageable pageable
-     *
      * @return Page
      */
     @NonNull
@@ -53,7 +51,6 @@ public interface CrudService<DOMAIN, ID> {
      * List all by ids
      *
      * @param ids ids
-     *
      * @return List
      */
     @NonNull
@@ -64,7 +61,6 @@ public interface CrudService<DOMAIN, ID> {
      *
      * @param ids  ids
      * @param sort sort
-     *
      * @return List
      */
     @NonNull
@@ -74,7 +70,6 @@ public interface CrudService<DOMAIN, ID> {
      * Fetch by id
      *
      * @param id id
-     *
      * @return Optional
      */
     @NonNull
@@ -84,33 +79,34 @@ public interface CrudService<DOMAIN, ID> {
      * Get by id
      *
      * @param id id
-     *
      * @return DOMAIN
+     * @throws NotFoundException If the specified id does not exist
      */
     @NonNull
     DOMAIN getById(@NonNull ID id);
 
     /**
-     * Get nullable by id
+     * Gets domain of nullable by id.
      *
      * @param id id
-     *
      * @return DOMAIN
      */
     @Nullable
-    DOMAIN getNullableById(@NonNull ID id);
+    DOMAIN getByIdOfNullable(@NonNull ID id);
 
     /**
-     * @param id id
+     * Exists by id.
      *
+     * @param id id
      * @return boolean
      */
     boolean existsById(@NonNull ID id);
 
     /**
-     * exist by id
+     * Must exist by id, or throw NotFoundException.
      *
      * @param id id
+     * @throws NotFoundException If the specified id does not exist
      */
     void mustExistById(@NonNull ID id);
 
@@ -125,7 +121,6 @@ public interface CrudService<DOMAIN, ID> {
      * save by domain
      *
      * @param domain domain
-     *
      * @return DOMAIN
      */
     @NonNull
@@ -135,47 +130,43 @@ public interface CrudService<DOMAIN, ID> {
      * save by domains
      *
      * @param domains domains
-     *
      * @return List
      */
     @NonNull
     List<DOMAIN> createInBatch(@NonNull Collection<DOMAIN> domains);
 
     /**
-     * Update by domain
+     * Updates by domain
      *
      * @param domain domain
-     *
      * @return DOMAIN
      */
     @NonNull
     DOMAIN update(@NonNull DOMAIN domain);
 
     /**
-     * Update by domains
+     * Updates by domains
      *
      * @param domains domains
-     *
      * @return List
      */
     @NonNull
     List<DOMAIN> updateInBatch(@NonNull Collection<DOMAIN> domains);
 
     /**
-     * Remove by id
+     * Removes by id
      *
      * @param id id
-     *
      * @return DOMAIN
+     * @throws NotFoundException If the specified id does not exist
      */
     @NonNull
     DOMAIN removeById(@NonNull ID id);
 
     /**
-     * Remove by id
+     * Removes by id if present.
      *
      * @param id id
-     *
      * @return DOMAIN
      */
     @Nullable
diff --git a/src/main/java/cc/ryanc/halo/service/impl/OptionsServiceImpl.java b/src/main/java/cc/ryanc/halo/service/impl/OptionsServiceImpl.java
index 1276232e9..041ca933c 100755
--- a/src/main/java/cc/ryanc/halo/service/impl/OptionsServiceImpl.java
+++ b/src/main/java/cc/ryanc/halo/service/impl/OptionsServiceImpl.java
@@ -117,7 +117,7 @@ public class OptionsServiceImpl extends AbstractCrudService<Options, String> imp
      */
     @Override
     public String findOneOption(String key) {
-//        final Options options = getNullableById(key);
+//        final Options options = getByIdOfNullable(key);
 //        if (null != options) {
 //            return options.getOptionValue();
 //        }
diff --git a/src/main/java/cc/ryanc/halo/task/PostSyncTask.java b/src/main/java/cc/ryanc/halo/task/PostSyncTask.java
index 16e7da299..ac6e52cc9 100644
--- a/src/main/java/cc/ryanc/halo/task/PostSyncTask.java
+++ b/src/main/java/cc/ryanc/halo/task/PostSyncTask.java
@@ -21,7 +21,7 @@ public class PostSyncTask {
         final PostService postService = SpringUtil.getBean(PostService.class);
         int count = 0;
         for (Long key : POSTS_VIEWS.keySet()) {
-            Post post = postService.getNullableById(key);
+            Post post = postService.getByIdOfNullable(key);
             if (null != post) {
                 post.setPostViews(post.getPostViews() + POSTS_VIEWS.get(key));
                 postService.create(post);