Java swing components layout position changes after restoring a minimized window

I'm developing a Flight Information Display(FIDs) Application that displays information with JLabels. I have different JPanels that contains different labels.

My issue is that when I launch the window, it displays properly with each components maintaining its desired layout position but the label position changes (clusters at the center) when you try to restore the window after minimizing it. Thereby clustering all the labels together. Please I really need to resolve this.

Below is my code snippet:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Departure extends javax.swing.JFrame {

    final private JPanel container = new JPanel();
    final private JPanel secPanel;
    final private JPanel imgPanel;
    final private JLabel logo;
    final private JLabel lagosLbl;
    final private JLabel londonLbl;
    final private JLabel newYorkLbl;
    final private JLabel lagosTime;
    final private JLabel londonTime;
    final private JLabel newYorkTime;
    final private JLabel departureLbl;
    final private JLabel airlineHd;
    final private JLabel flightHd;
    final private JLabel destHd;
    final private JLabel schedHd;
    final private JLabel gateHd;
    final private JLabel statusHd;
    final private JLabel footer;
    private JLabel footerLeft, footerMid, footerRight;


    private String todayDate, timeLocale, timeLondon, timeNewYork;

    Dimension sizeMain, sizeHeading, sizeBody, sizeLogo, sizeSec, screenSize;
    Insets insetsMain, insetsHeading, insetsBody, insetsLogo, insetsSec;

    public Departure(){

        super("DEPARTURES");

        screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        setBounds(0,0,screenSize.width, screenSize.height);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLocationRelativeTo(null);
        this.setResizable(false);      
        this.setVisible(true);



        container.setPreferredSize(new Dimension(screenSize.width, 
        screenSize.height));
        container.setBackground(new Color(53,86,163));
        this.getContentPane().add(container);

        Insets insets = this.getInsets();
        Dimension size = container.getPreferredSize();
        container.setBounds(0 + insets.left, 0 + insets.top,
        size.width + 5, size.height + 5);
        container.setLayout(null);


        ImageIcon icon = new ImageIcon(getClass().getResource("headerDe.jpg"));
        logo = new JLabel();
        logo.setIcon(new 
        ImageIcon(icon.getImage().getScaledInstance(screenSize.width, 200,
        java.awt.Image.SCALE_SMOOTH)));
        logo.setBackground(new Color(0,0,0));
        container.add(logo);

        insetsMain = container.getInsets();
        sizeMain = logo.getPreferredSize();
        logo.setBounds(0 + insetsMain.left, 0 + insetsMain.top,
        sizeMain.width + 5, sizeMain.height + 5);


        lagosLbl = new JLabel("LAGOS:");
        lagosLbl.setFont(new Font("Century Gothic",Font.BOLD, 40));
        lagosLbl.setForeground(new Color(0,0,140));
        logo.add(lagosLbl);

        insetsLogo = logo.getInsets();
        sizeLogo = lagosLbl.getPreferredSize();
        lagosLbl.setBounds(1550 + insetsLogo.left, 5 + insetsLogo.top,
        sizeLogo.width + 5, sizeLogo.height + 5);

        timeLocale = myTimeLocale();
        lagosTime = new JLabel(timeLocale);
        lagosTime.setFont(new Font("Century Gothic",Font.BOLD, 45));
        lagosTime.setForeground(new Color(0,0,140));
        logo.add(lagosTime);

        sizeLogo = lagosTime.getPreferredSize();
        lagosTime.setBounds(1750 + insetsLogo.left, 2 + insetsLogo.top,
        sizeLogo.width + 5, sizeLogo.height + 5);


        londonLbl = new JLabel("LONDON:");
        londonLbl.setFont(new Font("Century Gothic",Font.BOLD, 40));
        londonLbl.setForeground(new Color(0,0,140));
        logo.add(londonLbl);

        sizeLogo = londonLbl.getPreferredSize();
        londonLbl.setBounds(1515 + insetsLogo.left, 65 + insetsLogo.top,
        sizeLogo.width + 5, sizeLogo.height + 5);

        timeLondon = myTimeLondon();
        londonTime = new JLabel(timeLondon);
        londonTime.setFont(new Font("Century Gothic",Font.BOLD, 45));
        londonTime.setForeground(new Color(0,0,140));
        logo.add(londonTime);

        sizeLogo = londonTime.getPreferredSize();
        londonTime.setBounds(1750 + insetsLogo.left, 62 + insetsLogo.top,
        sizeLogo.width + 5, sizeLogo.height + 5);

        newYorkLbl = new JLabel("NEW YORK:");
        newYorkLbl.setFont(new Font("Century Gothic",Font.BOLD, 40));
        newYorkLbl.setForeground(new Color(0,0,140));
        logo.add(newYorkLbl);

        sizeLogo = newYorkLbl.getPreferredSize();
        newYorkLbl.setBounds(1485 + insetsLogo.left, 125 + insetsLogo.top,
        sizeLogo.width + 5, sizeLogo.height + 5);

        timeNewYork = myTimeNewYork();

        newYorkTime = new JLabel(timeNewYork);
        newYorkTime.setFont(new Font("Century Gothic",Font.BOLD, 45));
        newYorkTime.setForeground(new Color(0,0,140));
        myTimeNewYork();
        logo.add(newYorkTime);

        sizeLogo = newYorkTime.getPreferredSize();
        newYorkTime.setBounds(1750 + insetsLogo.left, 122 + insetsLogo.top,
        sizeLogo.width + 5, sizeLogo.height + 5);

        departureLbl = new JLabel("DEPARTURES");
        departureLbl.setFont(new Font("Century Gothic",Font.BOLD, 100));
        departureLbl.setForeground(new Color(53,86,163));
        logo.add(departureLbl);

        sizeLogo = departureLbl.getPreferredSize();
        departureLbl.setBounds(680 + insetsLogo.left, 50 + insetsLogo.top,
        sizeLogo.width + 5, sizeLogo.height + 5);


        secPanel = new JPanel();
        secPanel.setPreferredSize( new Dimension( screenSize.width, 
        (screenSize.width - 300) ) );
        secPanel.setBackground(new Color(255,255,255));
        container.add(secPanel);

        sizeMain = secPanel.getPreferredSize();
        secPanel.setBounds(0 + insetsMain.left, 200 + insetsMain.top,
        sizeMain.width + 5, sizeMain.height + 5);


        imgPanel = new JPanel();
        imgPanel.setPreferredSize( new Dimension( screenSize.width,45 ) );
        imgPanel.setBackground(new Color(0,0,140));
        secPanel.add(imgPanel);

        insetsHeading = secPanel.getInsets();
        sizeHeading = imgPanel.getPreferredSize();
        imgPanel.setBounds(0 + insetsHeading.left, 5 + insetsHeading.top,
        sizeHeading.width + 5, sizeHeading.height + 5);


        schedHd = new JLabel("STD");
        schedHd.setFont(new Font("Century Gothic",Font.BOLD, 28));
        schedHd.setForeground(new Color(255, 255, 255));
        imgPanel.add(schedHd);

        insetsHeading = imgPanel.getInsets();
        sizeHeading = schedHd.getPreferredSize();
        schedHd.setBounds(100 + insetsHeading.left, 5 + insetsHeading.top,
        sizeHeading.width + 5, sizeHeading.height + 5);

        airlineHd = new JLabel("AIRLINE");
        airlineHd.setFont(new Font("Century Gothic",Font.BOLD, 28));
        airlineHd.setForeground(new Color(255, 255, 255));
        imgPanel.add(airlineHd);

        sizeHeading = airlineHd.getPreferredSize();
        airlineHd.setBounds(350 + insetsHeading.left, 5 + insetsHeading.top,
        sizeHeading.width + 5, sizeHeading.height + 5);

        destHd = new JLabel("DESTINATION");
        destHd.setFont(new Font("Century Gothic",Font.BOLD, 28));
        destHd.setForeground(new Color(255, 255, 255));
        imgPanel.add(destHd);

        sizeHeading = destHd.getPreferredSize();
        destHd.setBounds(650 + insetsHeading.left, 5 + insetsHeading.top,
        sizeHeading.width + 5, sizeHeading.height + 5);

        flightHd = new JLabel("FLIGHT");
        flightHd.setFont(new Font("Century Gothic",Font.BOLD, 28));
        flightHd.setForeground(new Color(255, 255, 255));
        imgPanel.add(flightHd);   

        sizeHeading = flightHd.getPreferredSize();
        flightHd.setBounds(1020 + insetsHeading.left, 5 + insetsHeading.top,
        sizeHeading.width + 5, sizeHeading.height + 5);


        gateHd = new JLabel("GATE");
        gateHd.setFont(new Font("Century Gothic",Font.BOLD, 28));
        gateHd.setForeground(new Color(255, 255, 255));
        imgPanel.add(gateHd);

        sizeHeading = gateHd.getPreferredSize();
        gateHd.setBounds(1280 + insetsHeading.left, 5 + insetsHeading.top,
        sizeHeading.width + 5, sizeHeading.height + 5);

        statusHd = new JLabel("STATUS");
        statusHd.setFont(new Font("Century Gothic",Font.BOLD, 28));
        statusHd.setForeground(new Color(255, 255, 255));
        imgPanel.add(statusHd);

        sizeHeading = statusHd.getPreferredSize();
        statusHd.setBounds(1520 + insetsHeading.left, 5 + insetsHeading.top,
        sizeHeading.width + 5, sizeHeading.height + 5);

        ImageIcon foot = new ImageIcon(getClass().getResource("footer.jpg"));
        footer = new JLabel();
        footer.setIcon(new 
        ImageIcon(foot.getImage().getScaledInstance(screenSize.width, 70,
        java.awt.Image.SCALE_SMOOTH)));
        secPanel.add(footer);

        size = footer.getPreferredSize();
        footer.setBounds(0 + insets.left, 760 + insets.top,
        size.width + 5, size.height + 5);

        todayDate = dayOfWeek() + "    "+ myDate();
        footerLeft = new JLabel(todayDate);
        footerLeft.setFont(new Font("Century Gothic",Font.BOLD, 30));
        footerLeft.setForeground(new Color(255,255,255));
        footer.add(footerLeft);

        size = footerLeft.getPreferredSize();
        footerLeft.setBounds(15 + insets.left, 15 + insets.top,
        size.width + 5, size.height + 5);

        footerMid = new JLabel();
        //footerMid.setPreferredSize(new Dimension(120, 70));
        footerMid.setFont(new Font("Century Gothic",Font.BOLD, 30));
        footerMid.setForeground(new Color(255,255,255));
        footer.add(footerMid);

        size = footerMid.getPreferredSize();
        footerMid.setBounds(450 + insets.left, 15 + insets.top,
        size.width + 5, size.height + 5);

        footerRight = new JLabel();
        footerRight.setFont(new Font("Century Gothic",Font.BOLD, 30));
        footerRight.setForeground(new Color(255,255,255));
        footer.add(footerRight);

        size = footerRight.getPreferredSize();
        footerRight.setBounds(1540 + insets.left, 15 + insets.top,
        size.width + 5, size.height + 5);


    }

    public String dayOfWeek(){
        Date now = new Date();

        SimpleDateFormat simpleDateformat = new SimpleDateFormat("EEEE"); // the 
        day of the week in full
        //SimpleDateFormat simpleDateformat = new SimpleDateFormat("E"); // the 
        day of the week abbreviated
        return simpleDateformat.format(now);
    }

    protected static String myDate(){
        Calendar myD = Calendar.getInstance();

        SimpleDateFormat d = new SimpleDateFormat("dd/MM/yyyy");
        String date = (d.format(myD.getTime()));

        return date;
    }

    public static void main(String args []){
        Departure departure = new Departure();
    }
}

Thanks to everyone who responded to my question. I later find out that I didn't explicitly define the layout for each of the container(Panels) I declared before adding some contents (Labels) to them, thus the dimension tends to scatter when I restore the window. Though this may be cumbersome but I do enjoy having absolute control over the positioning of each of the item in the window. Thanks once again

Below is an example of how I resolved it;

//After initializing the imgPanel

imgPanel.setLayout(null); //explicitly declare the imgPanel layout to null

JLabel lbl = new JLabel("STD");
imgPanel.add(lbl)

Insets imgPanelInsets = imgPanel.getInsets(); //define the components insets
Dimension sizeImg = lbl.getPreferredSize(); //define the components dimension
lbl.setBounds(100 + imgPanelInsets.left, 5 + imgPanelInsets.top,
             sizeImg.width + 5, sizeImg.height + 5);  

JLabel lbl2 = new JLabel("AIRLINE");
imgPanel.add(lbl2)

sizeImg = lbl2.getPreferredSize();
lbl2.setBounds(100 + imgPanelInsets.left, 5 + imgPanelInsets.top,
             sizeImg.width + 5, sizeImg.height + 5);