package com.pengrad.telegrambot.model.request;

import com.google.gson.Gson;

/**
 * stas
 * 8/11/15
 */
public abstract class Keyboard {

    @Override
    public String toString() {
        return new Gson().toJson(this);
    }

}

@@ -157,16 +157,22 @@
  public 
+final 
 String t

Make toString() final in Keyboard