I was learning and noticing something different. For example:

Old codes:

public class MainActivity extends AppCompatActivity()
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

New codes:

package com.gusbemacbe.brakadictionary.main

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity()
{

override fun onCreate(savedInstanceState: Bundle?)
{
  super.onCreate(savedInstanceState)
  setContentView(R.layout.activity_main)
}

external fun stringFromJNI(): String

  companion object
  {

    init
      {
        System.loadLibrary("native-lib")
      }
  }
}

If I keep the new codes and add public static final String fileDictionary = "dicionario.txt";, it will not work.