Develop Reference

How do I make a panel visible inside frame in Java AWT?

I am studying Java AWT to create GUI applications. I am working on the below code where I cannot make the panel visible inside the frame. Here is my code:
import java.awt.*;
import java.awt.event.*;
/**
*
* #author kiran
*/
public class UserInterface
{
Frame UI;
private static double UIWidth, UIHeight;
/**
* Constructs User Interface
*/
public UserInterface()
{
UI = new Frame("frame");
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
UIWidth = screenSize.getWidth();
UIHeight = screenSize.getHeight();
buildFrame();
buildMessageInputArea();
}
/**
* returns the width of the UI
* #return returns the width of the UI
*/
public static double getUIWidth()
{
return UIWidth;
}
/**
* returns the width of the UI
* #return returns the width of the UI
*/
public static double getUIHeight()
{
return UIHeight;
}
/**
* Builds the frame
*/
private void buildFrame()
{
UI.setSize((int)UIWidth,(int)UIHeight*96/100);
UI.setVisible(true);
UI.setLayout(new FlowLayout());
UI.addWindowListener(new Actions());
}
private void buildMessageInputArea()
{
Panel current = new TextAreaPanel().getPanel();
current.setVisible(true);
UI.add(current);
}
}
class TextAreaPanel extends Frame
{
private Panel textAreaPanel;
TextArea msgInputArea;
public TextAreaPanel()
{
textAreaPanel = new Panel();
msgInputArea = new TextArea(1000,(int)UserInterface.getUIWidth() * 80/100);
}
private void addTextArea()
{
textAreaPanel.add(msgInputArea);
}
public Panel getPanel()
{
return textAreaPanel;
}
}
class Actions extends WindowAdapter
{
#Override
public void windowClosing(WindowEvent c)
{
System.exit(0);
}
}
How can I make the panel visible inside the frame?

How do I make a panel visible inside frame in Java AWT?
There were two fundamental problems with the code as seen, which can be fixed by changing the following:
Add the panel/text area to the GUI before setVisible(true) is called on the top level container.
While it is possible to add components to a container after it has been made visible, they require special handling, and it is not necessary in this case.
Add the text area to the panel!
Here is the code, turned into a Minimal, Complete, and Verifiable example by adding a main(String[]) method, with those two changes implemented, as well as more explanatory comments on other aspects of the code.
import java.awt.*;
import java.awt.event.*;
public class UserInterface {
Frame UI;
private static double UIWidth, UIHeight;
public static void main(String[] args) {
Runnable r = () -> {
new UserInterface();
};
EventQueue.invokeLater(r);
}
/**
* Constructs User Interface
*/
public UserInterface() {
UI = new Frame("frame");
// setting a GUI to full screen while accounting for the task
// bar can be achieved in a single line of code.
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
UIWidth = screenSize.getWidth();
UIHeight = screenSize.getHeight();
// these need to be called in the reverse order to ensure the
// components are added before the GUI is set visible.
buildMessageInputArea();
buildFrame();
}
/**
* returns the width of the UI
*
* #return returns the width of the UI
*/
public static double getUIWidth() {
return UIWidth;
}
/**
* returns the width of the UI
*
* #return returns the width of the UI
*/
public static double getUIHeight() {
return UIHeight;
}
/**
* Builds the frame
*/
private void buildFrame() {
UI.setSize((int) UIWidth, (int) UIHeight * 96 / 100);
UI.setVisible(true);
UI.setLayout(new FlowLayout());
UI.addWindowListener(new Actions());
}
private void buildMessageInputArea() {
Panel current = new TextAreaPanel().getPanel();
current.setVisible(true);
UI.add(current);
}
}
// does not need to be a fram
//class TextAreaPanel extends Frame {
class TextAreaPanel {
private Panel textAreaPanel;
TextArea msgInputArea;
public TextAreaPanel() {
textAreaPanel = new Panel();
// these number represent columns and rows, not pixels!
//msgInputArea = new TextArea(1000, (int) UserInterface.getUIWidth() * 80 / 100);
msgInputArea = new TextArea(40, 60);
// add the text area to the panel!
textAreaPanel.add(msgInputArea);
}
/** not called by anything else
private void addTextArea() {
textAreaPanel.add(msgInputArea);
}
**/
public Panel getPanel() {
return textAreaPanel;
}
}
// This can be achieved in a single line of code
class Actions extends WindowAdapter {
#Override
public void windowClosing(WindowEvent c) {
System.exit(0);
}
}
To add to / expand on the comments of #mKorbel & #camickr:
Why use AWT? See this answer for many good reasons to abandon AWT components in favor of Swing.
See Composition over inheritance.
The use of static in GUIs more commonly causes problems, than fixes them. Most (if not all) of the methods marked as static should be reduced to non-static with the code using an instance of the object to call the method.

JDialogPane with Focused password input field [duplicate]

When my application loads, which is made using netbeans, the first JTextField is automatically focused, and in this JTextField, I have written "Enter your Username", it will go away when the user clicks on this field, but when the application is loaded, this field is focused, means I can't see "Enter your Username", how to unfocus it on startup ?

A log-in would be best done in a modal dialog, but that introduces problems in that the method requestFocusInWindow() must be called after the component is visible, but that is blocked by the fact the dialog is modal!
This example uses Rob Camick's RequestFocusListener (as presented in Dialog Focus) to manage focus after the dialog is visible.
Note: That is how it appears before the user does anything. The password field is focused by default.
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
public class LoginRequired {
LoginRequired() {
JFrame f = new JFrame("Login Required");
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setResizable(false);
f.setSize(400, 300); // not recommended, but used here for convenience
f.setLocationByPlatform(true);
f.setVisible(true);
showLogin(f);
}
private void showLogin(JFrame frame) {
JPanel p = new JPanel(new BorderLayout(5,5));
JPanel labels = new JPanel(new GridLayout(0,1,2,2));
labels.add(new JLabel("User Name", SwingConstants.TRAILING));
labels.add(new JLabel("Password", SwingConstants.TRAILING));
p.add(labels, BorderLayout.LINE_START);
JPanel controls = new JPanel(new GridLayout(0,1,2,2));
JTextField username = new JTextField("Joe Blogs");
controls.add(username);
JPasswordField password = new JPasswordField();
password.addAncestorListener(new RequestFocusListener(false));
controls.add(password);
p.add(controls, BorderLayout.CENTER);
JOptionPane.showMessageDialog(
frame, p, "Log In", JOptionPane.QUESTION_MESSAGE);
System.out.println("User Name: " + username.getText());
System.out.println("Password: " + new String(password.getPassword()));
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
new LoginRequired();
});
}
}
/**
* Convenience class to request focus on a component.
*
* When the component is added to a realized Window then component will
* request focus immediately, since the ancestorAdded event is fired
* immediately.
*
* When the component is added to a non realized Window, then the focus
* request will be made once the window is realized, since the
* ancestorAdded event will not be fired until then.
*
* Using the default constructor will cause the listener to be removed
* from the component once the AncestorEvent is generated. A second constructor
* allows you to specify a boolean value of false to prevent the
* AncestorListener from being removed when the event is generated. This will
* allow you to reuse the listener each time the event is generated.
*/
class RequestFocusListener implements AncestorListener
{
private boolean removeListener;
/*
* Convenience constructor. The listener is only used once and then it is
* removed from the component.
*/
public RequestFocusListener()
{
this(true);
}
/*
* Constructor that controls whether this listen can be used once or
* multiple times.
*
* #param removeListener when true this listener is only invoked once
* otherwise it can be invoked multiple times.
*/
public RequestFocusListener(boolean removeListener)
{
this.removeListener = removeListener;
}
#Override
public void ancestorAdded(AncestorEvent e)
{
JComponent component = e.getComponent();
component.requestFocusInWindow();
if (removeListener)
component.removeAncestorListener( this );
}
#Override
public void ancestorMoved(AncestorEvent e) {}
#Override
public void ancestorRemoved(AncestorEvent e) {}
}

textField.setFocusable(false);
textField.setFocusable(true);
If, and only if, textField had focus, the next component in TAB-order order will get focus automatically. The effect is the same as a TAB press.
(not tested in a GUI with just one focusable component :) )

Use requestFocusInWindow() to set focus on some other component rather then your JTextfield first.
But i'd suggest not to alter the native focus system, rather setText(String s) on the JTextField after initComponents() call in the constructor (assumed to be in netbeans).
Further optional reading: How to Use the Focus Subsystem

I think giving keyboard focus to the username field is the correct behavior, assuming that's what the user needs to do first. Instead of clearing on focus, why not clear only after the user types something?:
import java.awt.*;
import javax.swing.*;
import javax.swing.text.Document;
public class PlaceholderTextField extends JTextField {
public static void main(final String[] args) {
final PlaceholderTextField tf = new PlaceholderTextField("");
tf.setColumns(20);
tf.setPlaceholder("All your base are belong to us!");
final Font f = tf.getFont();
tf.setFont(new Font(f.getName(), f.getStyle(), 30));
JOptionPane.showMessageDialog(null, tf);
}
private String placeholder;
public PlaceholderTextField() {
}
public PlaceholderTextField(
final Document pDoc,
final String pText,
final int pColumns)
{
super(pDoc, pText, pColumns);
}
public PlaceholderTextField(final int pColumns) {
super(pColumns);
}
public PlaceholderTextField(final String pText) {
super(pText);
}
public PlaceholderTextField(final String pText, final int pColumns) {
super(pText, pColumns);
}
public String getPlaceholder() {
return placeholder;
}
#Override
protected void paintComponent(final Graphics pG) {
super.paintComponent(pG);
if (placeholder.length() == 0 || getText().length() > 0) {
return;
}
final Graphics2D g = (Graphics2D) pG;
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.setColor(getDisabledTextColor());
g.drawString(placeholder, getInsets().left, pG.getFontMetrics()
.getMaxAscent() + getInsets().top);
}
public void setPlaceholder(final String s) {
placeholder = s;
}
}
If you really just want to remove focus, some options:
component.setFocusable(false);
KeyboardFocusManager.getCurrentKeyboardFocusManager().focusNextComponent();
KeyboardFocusManager.getCurrentKeyboardFocusManager().clearGlobalFocusOwner();

ActionListener for JLabel

I want to learn how to write an ActionListener for JLabel. I want to make a label that open a new frame for user when user clicks the label. Maybe MouseListener can work but I do not know how to make it.

I recommend using a JTextField rather than a JLabel for this use.
Being based on a component designed to be focusable, it allows an ActionListener and looks and feels more like an HTML link.
E.G.
That is how it appears when the mouse is hovering over the first link.
LinkLabel
/* License - LGPL
LinkLabel Using the Desktop Class
There are a lot of link labels. This one uses the Java 1.6+
Desktop class for its functionality, and is thereby suitable
for applets, applications launched using JWS, and 'standard'
(non-JWS) desktop applications.
Note that the Desktop class can be used with pre 1.6 JREs. It
is available through JDIC.
https://jdic.dev.java.net/nonav/documentation/javadoc/jdic/org/jdesktop/jdic/desktop/Desktop.html
*/
import java.awt.Desktop;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.JTextField;
import javax.swing.JPanel;
import javax.swing.JOptionPane;
import javax.swing.border.MatteBorder;
import javax.swing.border.Border;
import java.net.URI;
import java.io.File;
/**
A Java 1.6+ LinkLabel that uses the Desktop class for opening
the document of interest.
The Desktop.browse(URI) method can be invoked from applications,
applets and apps. launched using Java Webstart. In the latter
two cases, the usual fall-back methods are used for sandboxed apps
(see the JavaDocs for further details).
While called a 'label', this class actually extends JTextField,
to easily allow the component to become focusable using keyboard
navigation.
To successfully browse to a URI for a local File, the file name
must be constructed using a canonical path.
#author Andrew Thompson
#version 2008/08/23
*/
public class LinkLabel
// we extend a JTextField, to get a focusable component
extends JTextField
implements MouseListener, FocusListener, ActionListener {
/** The target or href of this link. */
private URI target;
public Color standardColor = new Color(0,0,255);
public Color hoverColor = new Color(255,0,0);
public Color activeColor = new Color(128,0,128);
public Color transparent = new Color(0,0,0,0);
public boolean underlineVisible = true;
private Border activeBorder;
private Border hoverBorder;
private Border standardBorder;
/** Construct a LinkLabel that points to the given target.
The URI will be used as the link text.*/
public LinkLabel(URI target) {
this( target, target.toString() );
}
/** Construct a LinkLabel that points to the given target,
and displays the text to the user. */
public LinkLabel(URI target, String text) {
super(text);
this.target = target;
}
/* Set the active color for this link (default is purple). */
public void setActiveColor(Color active) {
activeColor = active;
}
/* Set the hover/focused color for this link (default is red). */
public void setHoverColor(Color hover) {
hoverColor = hover;
}
/* Set the standard (non-focused, non-active) color for this
link (default is blue). */
public void setStandardColor(Color standard) {
standardColor = standard;
}
/** Determines whether the */
public void setUnderlineVisible(boolean underlineVisible) {
this.underlineVisible = underlineVisible;
}
/* Add the listeners, configure the field to look and act
like a link. */
public void init() {
this.addMouseListener(this);
this.addFocusListener(this);
this.addActionListener(this);
setToolTipText(target.toString());
if (underlineVisible) {
activeBorder = new MatteBorder(0,0,1,0,activeColor);
hoverBorder = new MatteBorder(0,0,1,0,hoverColor);
standardBorder = new MatteBorder(0,0,1,0,transparent);
} else {
activeBorder = new MatteBorder(0,0,0,0,activeColor);
hoverBorder = new MatteBorder(0,0,0,0,hoverColor);
standardBorder = new MatteBorder(0,0,0,0,transparent);
}
// make it appear like a label/link
setEditable(false);
setForeground(standardColor);
setBorder(standardBorder);
setCursor( new Cursor(Cursor.HAND_CURSOR) );
}
/** Browse to the target URI using the Desktop.browse(URI)
method. For visual indication, change to the active color
at method start, and return to the standard color once complete.
This is usually so fast that the active color does not appear,
but it will take longer if there is a problem finding/loading
the browser or URI (e.g. for a File). */
public void browse() {
setForeground(activeColor);
setBorder(activeBorder);
try {
Desktop.getDesktop().browse(target);
} catch(Exception e) {
e.printStackTrace();
}
setForeground(standardColor);
setBorder(standardBorder);
}
/** Browse to the target. */
public void actionPerformed(ActionEvent ae) {
browse();
}
/** Browse to the target. */
public void mouseClicked(MouseEvent me) {
browse();
}
/** Set the color to the hover color. */
public void mouseEntered(MouseEvent me) {
setForeground(hoverColor);
setBorder(hoverBorder);
}
/** Set the color to the standard color. */
public void mouseExited(MouseEvent me) {
setForeground(standardColor);
setBorder(standardBorder);
}
public void mouseReleased(MouseEvent me) {}
public void mousePressed(MouseEvent me) {}
/** Set the color to the standard color. */
public void focusLost(FocusEvent fe) {
setForeground(standardColor);
setBorder(standardBorder);
}
/** Set the color to the hover color. */
public void focusGained(FocusEvent fe) {
setForeground(hoverColor);
setBorder(hoverBorder);
}
public static void main(String[] args) throws Exception {
JPanel p = new JPanel(new GridLayout(0,1));
File f = new File(".","LinkLabel.java");
/* Filename must be constructed with a canonical path in
order to successfully use Desktop.browse(URI)! */
f = new File(f.getCanonicalPath());
URI uriFile = f.toURI();
LinkLabel linkLabelFile = new LinkLabel(uriFile);
linkLabelFile.init();
p.add(linkLabelFile);
LinkLabel linkLabelWeb = new LinkLabel(
new URI("http://sscce.org/"),
"SSCCE");
linkLabelWeb.setStandardColor(new Color(0,128,0));
linkLabelWeb.setHoverColor(new Color(222,128,0));
linkLabelWeb.init();
/* This shows a quirk of the LinkLabel class, the
size of the text field needs to be constrained to
get the underline to appear properly. */
p.add(linkLabelWeb);
LinkLabel linkLabelConstrain = new LinkLabel(
new URI("http://sdnshare.sun.com/"),
"SDN Share");
linkLabelConstrain.init();
/* ..and this shows one way to constrain the size
(appropriate for this layout).
Similar tricks can be used to ensure the underline does
not drop too far *below* the link (think BorderLayout
NORTH/SOUTH).
The same technique can also be nested further to produce
a NORTH+EAST packing (for example). */
JPanel labelConstrain = new JPanel(new BorderLayout());
labelConstrain.add( linkLabelConstrain, BorderLayout.EAST );
p.add(labelConstrain);
LinkLabel linkLabelNoUnderline = new LinkLabel(
new URI("http://java.net/"),
"java.net");
// another way to deal with the underline is to remove it
linkLabelNoUnderline.setUnderlineVisible(false);
// we can use the methods inherited from JTextField
linkLabelNoUnderline.
setHorizontalAlignment(JTextField.CENTER);
linkLabelNoUnderline.init();
p.add(linkLabelNoUnderline);
JOptionPane.showMessageDialog( null, p );
}
}

How to change JButton?

I want to make a JButton look like a link in HTML. It will still be a button and when I click on it it will open some new JFrame. But I want to change what it looks like. I tried this:
JButton button = new JButton();
button.setText("hi");
button.setContentAreaFilled(false);
button.setBorderPainted(false);
button.setOpaque(false);
button.setBackground(Color.WHITE);
button.setCursor(Cursor.getPredefinedCursor(12));
But there is still some border around the text of my button. How do we remove the border completely?

But there is still some border around the text of my button
button.setFocusPainted( false );

I recommend using a JTextField rather than a JButton for this use.
E.G.
That is how it appears when the mouse is hovering over the first link.
LinkLabel.java
/* License - LGPL
LinkLabel Using the Desktop Class
There are a lot of link labels. This one uses the Java 1.6+
Desktop class for its functionality, and is thereby suitable
for applets, applications launched using JWS, and 'standard'
(non-JWS) desktop applications.
Note that the Desktop class can be used with pre 1.6 JREs. It
is available through JDIC.
https://jdic.dev.java.net/nonav/documentation/javadoc/jdic/org/jdesktop/jdic/desktop/Desktop.html
*/
import java.awt.Desktop;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.JTextField;
import javax.swing.JPanel;
import javax.swing.JOptionPane;
import javax.swing.border.MatteBorder;
import javax.swing.border.Border;
import java.net.URI;
import java.io.File;
/**
A Java 1.6+ LinkLabel that uses the Desktop class for opening
the document of interest.
The Desktop.browse(URI) method can be invoked from applications,
applets and apps. launched using Java Webstart. In the latter
two cases, the usual fall-back methods are used for sandboxed apps
(see the JavaDocs for further details).
While called a 'label', this class actually extends JTextField,
to easily allow the component to become focusable using keyboard
navigation.
To successfully browse to a URI for a local File, the file name
must be constructed using a canonical path.
#author Andrew Thompson
#version 2008/08/23
*/
public class LinkLabel
// we extend a JTextField, to get a focusable component
extends JTextField
implements MouseListener, FocusListener, ActionListener {
/** The target or href of this link. */
private URI target;
public Color standardColor = new Color(0,0,255);
public Color hoverColor = new Color(255,0,0);
public Color activeColor = new Color(128,0,128);
public Color transparent = new Color(0,0,0,0);
public boolean underlineVisible = true;
private Border activeBorder;
private Border hoverBorder;
private Border standardBorder;
/** Construct a LinkLabel that points to the given target.
The URI will be used as the link text.*/
public LinkLabel(URI target) {
this( target, target.toString() );
}
/** Construct a LinkLabel that points to the given target,
and displays the text to the user. */
public LinkLabel(URI target, String text) {
super(text);
this.target = target;
}
/* Set the active color for this link (default is purple). */
public void setActiveColor(Color active) {
activeColor = active;
}
/* Set the hover/focused color for this link (default is red). */
public void setHoverColor(Color hover) {
hoverColor = hover;
}
/* Set the standard (non-focused, non-active) color for this
link (default is blue). */
public void setStandardColor(Color standard) {
standardColor = standard;
}
/** Determines whether the */
public void setUnderlineVisible(boolean underlineVisible) {
this.underlineVisible = underlineVisible;
}
/* Add the listeners, configure the field to look and act
like a link. */
public void init() {
this.addMouseListener(this);
this.addFocusListener(this);
this.addActionListener(this);
setToolTipText(target.toString());
if (underlineVisible) {
activeBorder = new MatteBorder(0,0,1,0,activeColor);
hoverBorder = new MatteBorder(0,0,1,0,hoverColor);
standardBorder = new MatteBorder(0,0,1,0,transparent);
} else {
activeBorder = new MatteBorder(0,0,0,0,activeColor);
hoverBorder = new MatteBorder(0,0,0,0,hoverColor);
standardBorder = new MatteBorder(0,0,0,0,transparent);
}
// make it appear like a label/link
setEditable(false);
setForeground(standardColor);
setBorder(standardBorder);
setCursor( new Cursor(Cursor.HAND_CURSOR) );
}
/** Browse to the target URI using the Desktop.browse(URI)
method. For visual indication, change to the active color
at method start, and return to the standard color once complete.
This is usually so fast that the active color does not appear,
but it will take longer if there is a problem finding/loading
the browser or URI (e.g. for a File). */
public void browse() {
setForeground(activeColor);
setBorder(activeBorder);
try {
Desktop.getDesktop().browse(target);
} catch(Exception e) {
e.printStackTrace();
}
setForeground(standardColor);
setBorder(standardBorder);
}
/** Browse to the target. */
public void actionPerformed(ActionEvent ae) {
browse();
}
/** Browse to the target. */
public void mouseClicked(MouseEvent me) {
browse();
}
/** Set the color to the hover color. */
public void mouseEntered(MouseEvent me) {
setForeground(hoverColor);
setBorder(hoverBorder);
}
/** Set the color to the standard color. */
public void mouseExited(MouseEvent me) {
setForeground(standardColor);
setBorder(standardBorder);
}
public void mouseReleased(MouseEvent me) {}
public void mousePressed(MouseEvent me) {}
/** Set the color to the standard color. */
public void focusLost(FocusEvent fe) {
setForeground(standardColor);
setBorder(standardBorder);
}
/** Set the color to the hover color. */
public void focusGained(FocusEvent fe) {
setForeground(hoverColor);
setBorder(hoverBorder);
}
public static void main(String[] args) throws Exception {
JPanel p = new JPanel(new GridLayout(0,1));
File f = new File(".","LinkLabel.java");
/* Filename must be constructed with a canonical path in
order to successfully use Desktop.browse(URI)! */
f = new File(f.getCanonicalPath());
URI uriFile = f.toURI();
LinkLabel linkLabelFile = new LinkLabel(uriFile);
linkLabelFile.init();
p.add(linkLabelFile);
LinkLabel linkLabelWeb = new LinkLabel(
new URI("http://pscode.org/sscce.html"),
"SSCCE");
linkLabelWeb.setStandardColor(new Color(0,128,0));
linkLabelWeb.setHoverColor(new Color(222,128,0));
linkLabelWeb.init();
/* This shows a quirk of the LinkLabel class, the
size of the text field needs to be constrained to
get the underline to appear properly. */
p.add(linkLabelWeb);
LinkLabel linkLabelConstrain = new LinkLabel(
new URI("http://sdnshare.sun.com/"),
"SDN Share");
linkLabelConstrain.init();
/* ..and this shows one way to constrain the size
(appropriate for this layout).
Similar tricks can be used to ensure the underline does
not drop too far *below* the link (think BorderLayout
NORTH/SOUTH).
The same technique can also be nested further to produce
a NORTH+EAST packing (for example). */
JPanel labelConstrain = new JPanel(new BorderLayout());
labelConstrain.add( linkLabelConstrain, BorderLayout.EAST );
p.add(labelConstrain);
LinkLabel linkLabelNoUnderline = new LinkLabel(
new URI("http://java.net/"),
"java.net");
// another way to deal with the underline is to remove it
linkLabelNoUnderline.setUnderlineVisible(false);
// we can use the methods inherited from JTextField
linkLabelNoUnderline.
setHorizontalAlignment(JTextField.CENTER);
linkLabelNoUnderline.init();
p.add(linkLabelNoUnderline);
JOptionPane.showMessageDialog( null, p );
}
}

try this, it should force it to set no border :
setBorder(BorderFactory.createEmptyBorder());

there are only one correct way, to change Look and Feel
or simple example for MetalButtonUI and Windows OS only

How can I get the Caps Lock state, and set it to on, if it isn't already?

I would like a specific example on how to turn caps lock on if it is off.
I know how to toggle the key, I have been using this:
toolkit.setLockingKeyState(KeyEvent.VK_CAPS_LOCK, Boolean.TRUE);
That will change the state of the key whether it is on or off.
But I want to make sure it is on at the beginning of the application.
(The final goal is having the keyboard LEDs flash in certain sequences, which works better if I have a certain starting state.)

You can use getLockingKeyState to check if Caps Lock is currently set:
boolean isOn = Toolkit.getDefaultToolkit().getLockingKeyState(KeyEvent.VK_CAPS_LOCK);
However, it's unnecessary -- setLockingKeyState doesn't toggle the state of the key, it sets it. If you pass it true it will set the key state to on regardless of the original state:
Toolkit.getDefaultToolkit().setLockingKeyState(KeyEvent.VK_CAPS_LOCK, true);

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package javaapplication52;
import java.awt.Toolkit;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;
/**
*
* #author DSF Inc - Admin
*/
public class JavaApplication52 extends JFrame {
JavaApplication52() {
setLayout(null);
JTextField t = new JTextField();
t.setBounds(0,0,300,20);
add(t);
t.addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent e) {
boolean isOn = Toolkit.getDefaultToolkit().getLockingKeyState(KeyEvent.VK_CAPS_LOCK);
if (isOn == true) {
System.err.println("ON");
} else {
System.err.println("OFF");
}
}
});
setSize(300, 400);
setVisible(true);
setResizable(false);
setLocationRelativeTo(null);
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
JavaApplication52 fr = new JavaApplication52();
}
}

Toolkit toolkit = Toolkit.getDefaultToolkit();
robik.keyPress(KeyEvent.VK_SPACE); // PRESS ANY KEY // Any key needs to be pressed
Toolkit.getDefaultToolkit().setLockingKeyState(KeyEvent.VK_CAPS_LOCK, true);
robik.keyRelease(KeyEvent.VK_SPACE);