Use the setVerticalAlignment() method to align JLabel text vertically to the top:JLabel label = label.setVerticalAlignment(JLabel.TOP);The following is an example to align JLabel text vertically to the top:Exampleimport java.awt.Color; import java.awt.Font; import javax.swing.*; import javax.swing.border.Border; public class SwingDemo {    public static void main(String args[]) {       JFrame frame = new JFrame("Demo");       JLabel label;       label = new JLabel("This is demo label!");       label.setFont(new Font("Verdana", Font.PLAIN, 14));       label.setVerticalAlignment(JLabel.TOP);       Border border = BorderFactory.createLineBorder(Color.ORANGE);       label.setBorder(border);       frame.add(label);       frame.setSize(600,300);       frame.setVisible(true);    } }Output

Mnemonic key is set so that a user can use Keyboard keys to check a CheckBox. For example, a key can be set with ALT:checkBox1.setMnemonic(KeyEvent.VK_F); checkBox2.setMnemonic(KeyEvent.VK_T); checkBox3.setMnemonic(KeyEvent.VK_R); checkBox4.setMnemonic(KeyEvent.VK_C); checkBox5.setMnemonic(KeyEvent.VK_A);Above, we have set key ALT+F for checkbox 1, key ALT+T for checkBox2, etc.The following is an example. Here, we have set Mnemonic key for selection of each CheckBox:Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class SwingDemo {    private JFrame mainFrame;    private JLabel headerLabel;    private JLabel statusLabel;    private JPanel controlPanel;    public SwingDemo(){       prepareGUI();    }    public static void main(String[] args){       ... Read More

Here, we have used ItemListener to handle JCheckBox events i.e. whenever any of the CheckBox is selected.For example; When any of the sports like Football CheckBox is checked, event is fired and a message is visible in the botton.The following is an example to handle JCheckBox events with an ItemListener:Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class SwingDemo {    private JFrame mainFrame;    private JLabel headerLabel;    private JLabel statusLabel;    private JPanel controlPanel;    public SwingDemo(){       prepareGUI();    }    public static void main(String[] args){       SwingDemo swingControlDemo = new SwingDemo();     ... Read More

The following is an example to get or set the selection state of JCheckBox:Exampleimport java.awt.FlowLayout; import javax.swing.JCheckBox; import javax.swing.JFrame; public class SwingDemo extends JFrame {    public SwingDemo() {       setSize(500, 500);       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       setLayout(new FlowLayout(FlowLayout.CENTER));       JCheckBox checkBox = new JCheckBox("Demo");       checkBox.setSelected(true);       boolean sel = checkBox.isSelected();       if (sel)          System.out.println("Check box selected!");       getContentPane().add(checkBox);    }    public static void main(String[] args) {       new SwingDemo().setVisible(true);    } }OutputSince the checkbox is selected by default, the following output would be visible in EclipseIDE:

The following is an example to disable JCheckBox if not checked in Java:Exampleimport java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JCheckBox; import javax.swing.JOptionPane; public class SwingDemo {    public static void main(String[] args) {       JCheckBox checkBox = new JCheckBox("Demo", true);       checkBox.addActionListener(new ActionListener() {          public void actionPerformed(ActionEvent e) {             if (checkBox.isEnabled())                checkBox.setEnabled(false);             else                checkBox.setEnabled(true);          }       });       JOptionPane.showMessageDialog(null, checkBox);    } }OutputNow, when you will uncheck the above checkbox, it will get disabled:

The following is an example to create JCheckBox from text in Swing:Exampleimport java.awt.FlowLayout; import javax.swing.JCheckBox; import javax.swing.JFrame; import javax.swing.JLabel; public class SwingDemo {    public static void main(String[] args) {       JCheckBox checkBox1 = new JCheckBox("Cricket");       JCheckBox checkBox2 = new JCheckBox("Squash");       JCheckBox checkBox3 = new JCheckBox("Football");       checkBox3.setSelected(true);       JCheckBox checkBox4 = new JCheckBox("Hockey");       JCheckBox checkBox5 = new JCheckBox("Fencing");       JCheckBox checkBox6 = new JCheckBox("Tennis");       JFrame frame = new JFrame();       frame.setLayout(new FlowLayout());       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   ... Read More

The following is an example to change JButton font dynamically:Exampleimport java.awt.Font; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; public class SwingDemo extends JFrame {    JButton button = new JButton("Change");    int fontSize = 10;    public SwingDemo() {       setSize(500, 400);       setDefaultCloseOperation(EXIT_ON_CLOSE);       add(button);       // changing font size dynamically on button click       button.addActionListener(new ActionListener() {          public void actionPerformed(ActionEvent ev) {             button.setFont(new Font("Dialog", Font.PLAIN, ++fontSize));             button.revalidate();          }       });       setVisible(true);    }    public static void main(String[] args) {       new SwingDemo();    } }OutputClick “Change” button above to change the font:

Let us first set a JButton:JButton btn = new JButton("DemoButton");Now, attach action listener:btn.addActionListener(new ClickListener());If you have an ActionListener attached to your button it'll fire when you call the method doClick():btn.doClick();The following is an example to call JButton doClick() method to simulate a click action:Exampleimport java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JOptionPane; public class SwingDemo {    public static void main(final String args[]) {       JButton btn = new JButton("DemoButton");       btn.addActionListener(new ClickListener());       JOptionPane.showMessageDialog(null, btn);       btn.doClick();    } } class ClickListener implements ActionListener {    public void actionPerformed(ActionEvent e) {   ... Read More

With set action command, here we are displaying a message in the console on the click of a button.Set the button first:JButton btn = new JButton("Demo Button");Now, set Action Listener to fire when the button is clicked:ActionListener actionListener = new ActionListener() {    public void actionPerformed(ActionEvent event) {       String str = event.getActionCommand();       System.out.println("Clicked = " + str);    } };The following is an example to set action command to JButton:Exampleimport java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JOptionPane; public class SwingDemo {    public static void main(final String args[]) {       JButton btn ... Read More

For Button border, use createLineBorder() method in Java, which allows you to set the color of the Border as well:JButton button = new JButton("Demo Button!"); Border border = BorderFactory.createLineBorder(Color.BLUE);The following is an example to change button border in Java:Exampleimport java.awt.BorderLayout; import java.awt.Color; import java.awt.Container; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.border.Border; public class SwingDemo {    public static void main(String args[]) {       JFrame frame = new JFrame("Button Border");       Container container = frame.getContentPane();       JButton button = new JButton("Demo Button!");       Border border = BorderFactory.createLineBorder(Color.BLUE);       button.setBorder(border);   ... Read More