import java.awt.*;
import javax.swing.*;

public class Build extends JFrame {

    public JPanel floor = new JPanel();
    public JFrame building = new JFrame();
//создание здания
    public void init_building() {
        building.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        building.pack();
        building.setVisible(true);
        building.setSize(600, 600);
        building.add(init_floor());

    }
//создание этажей
    public JPanel init_floor() {
        int floorAmount = 4;
        for (int i = 0; i < floorAmount; i++) {
            this.floor.setBounds(0, 100 * i, 400, 100);
            if (i % 2 == 0) {

                this.floor.setBackground(Color.black);
            } else {

                this.floor.setBackground(Color.white);
            }

        }

        return this.floor;

    }

    public static void main(String[] args) {
        EventQueue.invokeLater(
                new Runnable() {
                    public void run() {
                        Build q = new Build();
                        q.init_building();

                    }
                });
    }
}