Compute message entities content during Message deserialization

src/main/java/org/telegram/telegrambots/api/objects/Message.java

@@ -219,6 +219,10 @@ public class Message implements IBotApiObject {
         if (jsonObject.has(MIGRATEFROMCHAT_FIELD)) {
             this.migrateFromChatId = jsonObject.getLong(MIGRATEFROMCHAT_FIELD);
         }
+
+        if (hasText() && entities != null) {
+            entities.forEach(x -> x.computeText(text));
+        }
     }
 
     public Integer getMessageId() {

src/main/java/org/telegram/telegrambots/api/objects/MessageEntity.java

@@ -45,6 +45,8 @@ public class MessageEntity implements IBotApiObject {
     @JsonProperty(URL_FIELD)
     private String url; ///< Optional. For “text_link” only, url that will be opened after user taps on the text
 
+    private String text; ///< Text present in the entity. Computed from offset and length
+
     public MessageEntity() {
         super();
     }
@@ -75,6 +77,14 @@ public class MessageEntity implements IBotApiObject {
         return url;
     }
 
+    public String getText() {
+        return text;
+    }
+
+    protected void computeText(String message) {
+        text = message.substring(offset, offset + length);
+    }
+
     @Override
     public void serialize(JsonGenerator gen, SerializerProvider serializers) throws IOException {
         gen.writeStartObject();