Решил сравнить Swing и Qt в плане отрисовки окошек на небольшом примере из Qt Examples. Набросал аналогичный код на Java (см. ниже) и получилось у меня вот так:

Сразу же возникает вопрос: почему шрифт в JTextArea какой-то не правильный?
Но самое интересное, что при ресайзе этих окошек Qt все делает просто моментально и плавно, а в Java почему-то все происходит рывками и с заметным шлейфом от перерисовки рамки окна. Вопрос: что же я делаю не так? Или это вообще свойственно для Swing тормозить подобным образом даже для таких простых окошек?

Также глянул на вкладку Performance в Process Explorer для каждого из процессов:

Особенно заметна разница в потреблении памяти — java использует почти в 10 раз больше! Больше 100Мб для окошка, растянутого почти на весь экран, это нормально для Swing? Неужели действительно такая большая разница? Наверняка я что-то делаю не правильно...

Вот мой код на Java:

import static java.awt.GridBagConstraints.BOTH;
import static java.awt.GridBagConstraints.CENTER;
import static java.awt.GridBagConstraints.HORIZONTAL;
import static java.awt.GridBagConstraints.NONE;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;

import javax.swing.AbstractAction;
import javax.swing.Box;
import javax.swing.GroupLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSpinner;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.GroupLayout.ParallelGroup;
import javax.swing.GroupLayout.SequentialGroup;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.TitledBorder;

@SuppressWarnings("serial")
public class BasicLayouts extends JFrame {
  public BasicLayouts() {
    super("Basic layouts");
    // create components of window
    createMenuBar();
    Container horizontalLayout = createHorizontalGroupBox();
    Container gridLayout = createGridLayout();
    Container formLayout = createFormLayout();
    Container textArea = createTextArea();
    Container dialogButtons = createDialogButtons();
    // set group layout to content pane
    Container contentPane = getContentPane();
    GroupLayout mainLayout = new GroupLayout(contentPane);
    contentPane.setLayout(mainLayout);
    mainLayout.setAutoCreateContainerGaps(true);
    mainLayout.setAutoCreateGaps(true);
    // add components of window to group layout
    mainLayout.setHorizontalGroup(mainLayout.createParallelGroup()
        .addComponent(horizontalLayout).addComponent(gridLayout).addComponent(
            formLayout).addComponent(textArea).addComponent(dialogButtons));
    mainLayout.setVerticalGroup(mainLayout.createSequentialGroup()
        .addComponent(horizontalLayout).addComponent(gridLayout).addComponent(
            formLayout).addComponent(textArea).addComponent(dialogButtons));
    //
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    pack();
    setMinimumSize(getSize());
    setVisible(true);
  }

  private void createMenuBar() {
    JMenuBar menuBar = new JMenuBar();
    JMenu fileMenu = new JMenu("File");
    fileMenu.setMnemonic(KeyEvent.VK_F);
    JMenuItem exitItem = new JMenuItem(new AbstractAction() {
      {
        putValue(NAME, "Exit");
        putValue(MNEMONIC_KEY, KeyEvent.VK_X);
      }

      @Override
      public void actionPerformed(ActionEvent e) {
        System.exit(0);
      }
    });
    fileMenu.add(exitItem);
    menuBar.add(fileMenu);
    setJMenuBar(menuBar);
  }

  private Container createHorizontalGroupBox() {
    JPanel panel = new JPanel();
    GroupLayout groupLayout = new GroupLayout(panel);
    groupLayout.setAutoCreateGaps(true);
    final int nButtons = 4;
    SequentialGroup horizontalGroup = groupLayout.createSequentialGroup();
    ParallelGroup verticalGroup = groupLayout.createParallelGroup();
    for (int i = 1; i <= nButtons; i++) {
      JButton button = new JButton("Button " + i);
      horizontalGroup.addComponent(button, GroupLayout.DEFAULT_SIZE,
          GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE);
      verticalGroup.addComponent(button);
    }
    groupLayout.setHorizontalGroup(horizontalGroup);
    groupLayout.setVerticalGroup(verticalGroup);
    panel.setLayout(groupLayout);
    Insets insets = new Insets(2, 2, 2, 2);
    panel.setBorder(new CompoundBorder(new TitledBorder("Horizontal layout"),
        new EmptyBorder(insets)));
    return panel;
  }

  private Container createGridLayout() {
    JPanel panel = new JPanel();
    panel.setLayout(new GridBagLayout());
    JLabel label1st = new JLabel("Line 1:");
    JLabel label2nd = new JLabel("Line 2:");
    JLabel label3rd = new JLabel("Line 3:");
    JTextField textField1st = new JTextField();
    JTextField textField2nd = new JTextField();
    JTextField textField3rd = new JTextField();
    JTextArea textArea = new JTextArea(
        "This widget takes up about two thirds of the grid layout.");
    textArea.setLineWrap(true);
    textArea.setWrapStyleWord(true);
    JScrollPane scrollPane = new JScrollPane(textArea);
    Insets insets = new Insets(2, 2, 2, 2);
    panel.setBorder(new CompoundBorder(new TitledBorder("Grid layout"),
        new EmptyBorder(insets)));
    Component glue = Box.createGlue();
    panel.add(glue, new GridBagConstraints(0, 0, 2, 1, 0.5, 1.0, CENTER, BOTH,
        insets, 0, 0));
    panel.add(label1st, new GridBagConstraints(0, 1, 1, 1, 0.0, 0.0, CENTER,
        NONE, insets, 0, 0));
    panel.add(label2nd, new GridBagConstraints(0, 2, 1, 1, 0.0, 0.0, CENTER,
        NONE, insets, 0, 0));
    panel.add(label3rd, new GridBagConstraints(0, 3, 1, 1, 0.0, 0.0, CENTER,
        NONE, insets, 0, 0));
    panel.add(textField1st, new GridBagConstraints(1, 1, 1, 1, 0.5, 0.0,
        CENTER, HORIZONTAL, insets, 0, 0));
    panel.add(textField2nd, new GridBagConstraints(1, 2, 1, 1, 0.5, 0.0,
        CENTER, HORIZONTAL, insets, 0, 0));
    panel.add(textField3rd, new GridBagConstraints(1, 3, 1, 1, 0.5, 0.0,
        CENTER, HORIZONTAL, insets, 0, 0));
    panel.add(scrollPane, new GridBagConstraints(2, 0, 1, 4, 1.0, 1.0, CENTER,
        BOTH, insets, 0, 0));
    Dimension zeroSize = new Dimension(0,
        textField1st.getPreferredSize().height);
    textField1st.setPreferredSize(zeroSize);
    textField2nd.setPreferredSize(zeroSize);
    textField3rd.setPreferredSize(zeroSize);
    scrollPane.setPreferredSize(zeroSize);
    return panel;
  }

  private Container createFormLayout() {
    JPanel panel = new JPanel();
    GroupLayout groupLayout = new GroupLayout(panel);
    groupLayout.setAutoCreateGaps(true);
    JLabel label1st = new JLabel("Line 1:");
    JLabel label2nd = new JLabel("Line 2, long text:");
    JLabel label3rd = new JLabel("Line 3:");
    JTextField textField = new JTextField();
    JComboBox comboBox = new JComboBox();
    JSpinner spinner = new JSpinner();
    groupLayout.setHorizontalGroup(groupLayout.createSequentialGroup()
        .addGroup(
            groupLayout.createParallelGroup().addComponent(label1st)
                .addComponent(label2nd).addComponent(label3rd)).addGroup(
            groupLayout.createParallelGroup().addComponent(textField)
                .addComponent(comboBox).addComponent(spinner)));
    groupLayout.setVerticalGroup(groupLayout.createSequentialGroup().addGroup(
        groupLayout.createParallelGroup(GroupLayout.Alignment.BASELINE)
            .addComponent(label1st).addComponent(textField)).addGroup(
        groupLayout.createParallelGroup(GroupLayout.Alignment.BASELINE)
            .addComponent(label2nd).addComponent(comboBox,
                GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE,
                GroupLayout.PREFERRED_SIZE)).addGroup(
        groupLayout.createParallelGroup(GroupLayout.Alignment.BASELINE)
            .addComponent(label3rd).addComponent(spinner)));
    panel.setLayout(groupLayout);
    Insets insets = new Insets(2, 2, 2, 2);
    panel.setBorder(new CompoundBorder(new TitledBorder("Form layout"),
        new EmptyBorder(insets)));
    return panel;
  }

  private Container createTextArea() {
    JTextArea textArea = new JTextArea(
        "This widget takes up all the remaining space "
            + "in the top-level layout.");
    textArea.setLineWrap(true);
    textArea.setRows(4);
    return new JScrollPane(textArea);
  }

  private Container createDialogButtons() {
    JPanel panel = new JPanel();
    JButton ok = new JButton("OK");
    JButton cancel = new JButton("Cancel");
    GroupLayout groupLayout = new GroupLayout(panel);
    groupLayout.setAutoCreateGaps(true);
    groupLayout.setHorizontalGroup(groupLayout.createSequentialGroup().addGap(
        0, 0, Short.MAX_VALUE).addComponent(ok).addComponent(cancel));
    groupLayout.setVerticalGroup(groupLayout.createParallelGroup()
        .addComponent(ok).addComponent(cancel));
    groupLayout.linkSize(ok, cancel);
    panel.setLayout(groupLayout);
    return panel;
  }

  public static void main(String[] args) {
    try {
      UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    } catch (Exception e) {
      e.printStackTrace();
    }
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        new BasicLayouts();
      }
    });
  }
}