diff --git a/src/main/java/org/ntlab/amaryllis/server/entities/Comment.java b/src/main/java/org/ntlab/amaryllis/server/entities/Comment.java
new file mode 100644
index 0000000..933ecc2
--- /dev/null
+++ b/src/main/java/org/ntlab/amaryllis/server/entities/Comment.java
@@ -0,0 +1,27 @@
+package org.ntlab.amaryllis.server.entities;
+
+
+import org.w3c.dom.Text;
+
+import java.util.UUID;
+
+import static java.util.UUID.randomUUID;
+
+public class Comment {
+    String cid;//commentId
+    String uid;
+    String text;
+
+    public Comment(String uid, String text) {
+        this.cid = randomUUID().toString();
+        this.uid = uid;
+        this.text = text;
+    }
+
+    public String getCid(){ return cid; }
+
+    public String getUid(){ return uid; }
+
+    public String getText(){ return text; }
+
+}
diff --git a/src/main/java/org/ntlab/amaryllis/server/entities/Voicememo.java b/src/main/java/org/ntlab/amaryllis/server/entities/Voicememo.java
index 019ae38..dddf2dd 100644
--- a/src/main/java/org/ntlab/amaryllis/server/entities/Voicememo.java
+++ b/src/main/java/org/ntlab/amaryllis/server/entities/Voicememo.java
@@ -1,7 +1,6 @@
 package org.ntlab.amaryllis.server.entities;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
-
 import java.awt.datatransfer.FlavorListener;
 import java.util.ArrayList;
 import java.util.Calendar;
@@ -21,9 +20,7 @@
     private ArrayList<String> favolist;
     private Integer favos;
     private ArrayList<String> categories;
-    private ArrayList<Integer> comments_commentNo;
-    private ArrayList<String> comments_uid;
-    private ArrayList<String> comments_comment;
+    private ArrayList<Comment> comments;
 
     public Voicememo(String vid, String uid, Integer time, String data, double latitude, double longitude, String title, String summary) {
 
@@ -41,10 +38,7 @@
         this.times = 0;
         this.favos = 0;
 //        categories = new ArrayList<>();
-//        comments_commentNo = new ArrayList<>();
-//        comments_uid = new ArrayList<>();
-//        comments_comment = new ArrayList<>();
-
+//        comments = new ArrayList<>();
     }
 
 
@@ -62,7 +56,6 @@
         this.vid = vid;
     }
 
-
     private String getUid() {
         return uid;
     }
@@ -165,14 +158,54 @@
     private void setFavos(){
         favos = favolist.size();
     }
+
 //
 //    public ArrayList<String> getCategory(){ return categories; }
 //
-//    public ArrayList<Integer> getComments_commentNo(){ return comments_commentNo; }
+//    public void addCategory(String categoryId){
+//        for (String a : categories) {
+//            if (a.equals(categoryId)) {
+//                return;
+//            }
+//        }
+//        categories.add(categoryId);
+//    }
 //
-//    public ArrayList<String> getComments_uid(){ return comments_uid; }
+//    public void removeCategory(String CategoryId) {
+//        categories.remove(CategoryId);
+//    }
 //
-//    public ArrayList<String> getComments_comment(){ return comments_comment; }
+//
+//    public ArrayList<Comment> getComments(){ return comments; }
+//
+//    public Comment getComment(String cid) {
+//        if(cid.equals(null)){
+//            return null;
+//        }
+//        for (Comment a : comments) {
+//            if (a.getCid().equals(cid)) {
+//                return a;
+//            }
+//        }
+//        return null;
+//    }
+//
+//    public Comment createComment(String uid, String text) {
+//        if (uid == null || text == null) {
+//            return null;
+//        }
+//        Comment newComment = new Comment(uid, text);
+//        comments.add(newComment);
+//        return newComment;
+//    }
+//
+//    public void removeComment(String cid) {
+//        if(cid.equals(null)){
+//            return;
+//        }
+//        Comment removeComment = getComment(cid);
+//        comments.remove(removeComment);
+//    }
 
 
 }
diff --git a/src/main/java/org/ntlab/amaryllis/server/models/Voicememos.java b/src/main/java/org/ntlab/amaryllis/server/models/Voicememos.java
index edcaecb..d6a3283 100644
--- a/src/main/java/org/ntlab/amaryllis/server/models/Voicememos.java
+++ b/src/main/java/org/ntlab/amaryllis/server/models/Voicememos.java
@@ -20,16 +20,12 @@
         return theInstance;
     }
 
-    public static String createVid() {
+    private static String createVid() {
         String vid = UUID.randomUUID().toString();
         return vid;
     }
 
     public Voicememo getVoicememo(String vid) {
-        if(vid.equals(null)){
-            return null;
-        }
-
         for (Voicememo a : voicememos) {
             if (a.getVid().equals(vid)) {
                 return a;
@@ -57,10 +53,6 @@
     }
 
     public void removeVoicememo(String vid) {
-        if(vid.equals(null)){
-            return;
-        }
-
         Voicememo removeVoicememo = getVoicememo(vid);
         voicememos.remove(removeVoicememo);
     }