diff --git a/src/main/java/org/ntlab/amaryllis/server/entities/Comment.java b/src/main/java/org/ntlab/amaryllis/server/entities/Comment.java
index 8deb43d..6e6d2b2 100644
--- a/src/main/java/org/ntlab/amaryllis/server/entities/Comment.java
+++ b/src/main/java/org/ntlab/amaryllis/server/entities/Comment.java
@@ -10,16 +10,16 @@
     String uid;
     String text;
 
-    public Comment(String uid, String text) {
-        this.commentId = randomUUID().toString();
+    public Comment(String commentId, String uid, String text) {
+        this.commentId = commentId;
         this.uid = uid;
         this.text = text;
     }
 
-    public String getCid(){ return commentId; }
+    public String getCommentId(){ return commentId; }
 
     public String getUid(){ return uid; }
 
     public String getText(){ return text; }
 
-}
+}
\ No newline at end of file
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 d072773..80ad11c 100644
--- a/src/main/java/org/ntlab/amaryllis/server/entities/Voicememo.java
+++ b/src/main/java/org/ntlab/amaryllis/server/entities/Voicememo.java
@@ -1,9 +1,8 @@
 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;
+
+import java.util.*;
 
 public class Voicememo {
     private String vid;
@@ -20,7 +19,7 @@
     private ArrayList<String> favolist;
     private Integer favos;
     private ArrayList<String> categories;
-    private ArrayList<Comment> comments;
+    private HashMap<String,Comment> commentMap = new HashMap<>();
 
     public Voicememo(String vid, String uid, Integer time, String url, double latitude, double longitude, String title, String summary) {
 
@@ -37,8 +36,6 @@
         setSummary(summary);
         this.times = 0;
         this.favos = 0;
-        categories = new ArrayList<>();
-        comments = new ArrayList<>();
     }
 
     public String getVid() {
@@ -152,7 +149,6 @@
         favos = favolist.size();
     }
 
-
     public ArrayList<String> getCategory(){ return categories; }
 
     public void addCategory(String categoryId){
@@ -168,30 +164,26 @@
         categories.remove(CategoryId);
     }
 
-
-    public ArrayList<Comment> getComments(){ return comments; }
+    public Collection<Comment> getComments() {
+        return commentMap.values();
+    }
 
     public Comment getComment(String commentId) {
-        for (Comment a : comments) {
-            if (a.getCid().equals(commentId)) {
-                return a;
-            }
-        }
-        return null;
+        return commentMap.get(commentId);
     }
 
     public Comment createComment(String uid, String text) {
         if (uid == null || text == null) {
             return null;
         }
-        Comment newComment = new Comment(uid, text);
-        comments.add(newComment);
+        String commentId = UUID.randomUUID().toString();
+        Comment newComment = new Comment(commentId, uid, text);
+        commentMap.put(commentId,newComment);
         return newComment;
     }
 
     public void removeComment(String commentId) {
-        Comment removeComment = getComment(commentId);
-        comments.remove(removeComment);
+        commentMap.remove(commentId);
     }