Andorid connect dabase error 'java.sql.Statement java.sql.Connection.createStatement()' on a null object reference

package com.example.boonmapi.myapplication;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.os.StrictMode;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleAdapter;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public class MainActivity extends AppCompatActivity {

    Button EXECUTAR;
    EditText ValorBusca;
    ListView Lista;
    Connection connect;
    SimpleAdapter AD;

    private  void  declarar(){
        EXECUTAR = (Button) findViewById(R.id.btn_buscar);
        ValorBusca =(EditText)findViewById(R.id.txt_buscar);
        Lista =(ListView)findViewById(R.id.list_output);

    }
    private  void inicializer() {
        declarar();
        ValorBusca.setText("SELECT TOP 10 * FROM ES_LOG");
        connect = CONN("boonmapi","031981209","DB_MAEJOPHRAE","PAKPOOM\\SQLEXPRESS");
    }

    @SuppressLint("NewApi")
    public   Connection  CONN (String user,String pass,String DB,String server) {


        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        Connection conn = null;
        String ConnURL = null;

        try {
            Class.forName("net.sourceforge.jtds.jdbc.Driver");
            ConnURL = "jdbc:jtds:sqlserver://" + server + ";" + "databaseName=" + DB + ";user=" + user + ";password=" + pass + ";"+ "ssl=false";
            conn = DriverManager.getConnection(ConnURL);


        } catch (SQLException se) {
            Log.e("ERRO", se.getMessage());
        } catch (ClassNotFoundException e) {
            Log.e("ERRO", e.getMessage());
        } catch (Exception e) {
            Log.e("ERRO", e.getMessage());
        }
        return conn;
    }


    public void QuerySQL(String COMANDOSQL){

        try {

            Statement stmt = connect.createStatement();



            ResultSet rs = stmt.executeQuery(COMANDOSQL);

            List<Map<String,String>> data = null;

            data =new ArrayList<Map<String, String>>();

            while (rs.next()){
                Map<String,String> datanum = new HashMap<String, String>();
                datanum.put("A", rs.getString("USERNAME"));
                datanum.put("B", rs.getString("DATA"));
                data.add(datanum);
                System.out.println( rs.getString("DATA"));
            }
            String[] from = {"A","B"};
            int[] views={R.id.txt_titulo,R.id.txt_conteudo};
            AD = new SimpleAdapter(this,data,R.layout.modelo,from,views);
            Lista.setAdapter(AD);

        }catch (Exception e){
            Log.e("ERRO",e.getMessage());
           System.out.println(COMANDOSQL );
        }

    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        inicializer();

        EXECUTAR.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                QuerySQL(ValorBusca.getText().toString());

            }
        });
    }
}