JFrame.setExtendedState（）在Mac上无法正常工作

Question

I am using a javax.swing.JFrame with java 1.8.0_211 and I want to have my JFrame maximized over the whole screen.

I am using the following code:

public class MitarbeiterUI extends javax.swing.JFrame {


    /**
     * Creates new form MitarbeiterUI
     */
    public MitarbeiterUI(Mitarbeiter mitarbt) {

        initComponents();

        this.setExtendedState(MAXIMIZED_BOTH);
        this.setSize((int)Toolkit.getDefaultToolkit().getScreenSize().getWidth(), (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight());
        this.setVisible(true);
    }

    [...]
}

This however only causes the window to align to the screen horizontally, but not vertically. It does work with both Windows And Linux systems, so it has to be a Mac specific issue. Is there any way around this mighty annoying bug?

Edit: Executable code sample

import java.awt.Toolkit;

public class SecondFrame extends javax.swing.JFrame {

/**
 * Creates new form SecondFrame
 */
public SecondFrame() {
    initComponents();

    this.setExtendedState(MAXIMIZED_BOTH);
    this.setSize((int)Toolkit.getDefaultToolkit().getScreenSize().getWidth(), (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight());
    this.setVisible(true);
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jLabel1 = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    addComponentListener(new java.awt.event.ComponentAdapter() {
        public void componentResized(java.awt.event.ComponentEvent evt) {
            formComponentResized(evt);
        }
    });

    jPanel1.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED));

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 563, Short.MAX_VALUE)
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 877, Short.MAX_VALUE)
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(134, 134, 134)
                    .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(layout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(jLabel1)))
            .addContainerGap(25, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addGap(19, 19, 19)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(241, Short.MAX_VALUE))
    );

    pack();
}// </editor-fold>                        

private void formComponentResized(java.awt.event.ComponentEvent evt) {                                      
    jLabel1.setText("W: " + this.getWidth() + ", H: " + this.getHeight());
}                                     

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(SecondFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(SecondFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(SecondFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(SecondFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new SecondFrame().setVisible(true);
        }
    });
}

// Variables declaration - do not modify                     
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel jPanel1;
// End of variables declaration                   
}

Edit2: It seems the issue lies with the screen sizes the Macs we used have. They both sport a resolution greater than fullHD, but both are automatically scaling down to 1440 to 900p, which makes the JPanel we use in our class bigger than the resized screen and in turn has it cut off at the bottom. So I guess the question is now how can I either tell those Macs to not resize their screens, or how to add scrollbars to the JFrame without having to redo the whole class.

Answer 1

this.setExtendedState(MAXIMIZED_BOTH);
this.setSize((int)Toolkit.getDefaultToolkit().getScreenSize().getWidth(), (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight());
this.setVisible(true);

The point of using setExtendedState(...) is that you don't need to use the setSize(...) method.

So the code should simply be:

this.setExtendedState(MAXIMIZED_BOTH);
this.setVisible(true);

The setSize() statement is overriding the size calculated by the setExtendedState(...) method.