Name: dbT83986 Date: 03/30/99


This is a bug reported against jdk 1.1.8 release candidate, used
with swing 1.1.

When clicking on a menu bar or menu item, an UnsatisfiedLinkError
occurs.

1. Compile and run the application from the source code included
below. Use the mouse and click on the 'File' menu, then the 'New'
menu item.

2. I used this source code, taken from the examples provided with
Core Java Foundation Classes, ISBN 0-13-080301-4:

package JFCBook.Chapter6;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;

public class MenuExample2 extends JFrame {
public MenuExample2(String title) {
super(title);

JMenuBar mb = new JMenuBar();
this.setJMenuBar(mb);

JMenu fileMenu = new JMenu("File");
mb.add(fileMenu);

newItem = new JMenuItem("New...");
openItem = new JMenuItem("Open...");
closeItem = new JMenuItem("Close");
fileMenu.add(newItem);
fileMenu.add(openItem);
fileMenu.add(closeItem);

fileMenu.addSeparator();

saveItem = new JMenuItem("Save");
saveAsItem = new JMenuItem("Save As...");
fileMenu.add(saveItem);
fileMenu.add(saveAsItem);

fileMenu.addSeparator();

fileListMenu = new JMenu("Recent Files");
fileMenu.add(fileListMenu);
emptyListItem = new JMenuItem("Empty");
emptyListItem.setEnabled(false);
fileListMenu.add(emptyListItem);

fileMenu.addSeparator();

JMenuItem exitItem = new JMenuItem("Exit");
fileMenu.add(exitItem);
exitItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
closeWindow();
}
});

this.getContentPane().add(new JScrollPane(textArea = new JTextArea(20, 40)));
fileManager = new FileManager();

// Processing for "New..." menu item
newItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
String name = getFileName("New File", FileDialog.SAVE);
if (name != null) {
if (fileManager.isFileOpen()) {
// Close any open file
try {
fileManager.closeFile(textArea.getText());
} catch (Throwable e) {
// Ignore any exception
}
}
try {
fileManager.newFile(name);
textArea.setText("");
addRecentFile(name);
} catch (IOException e) {
// Do nothing - message already printed
}
}
}
});

// Processing for "Open..." menu item
openItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
String name = getFileName("Open File", FileDialog.LOAD);
if (name != null) {
try {
String text = fileManager.openFile(name);
textArea.setText(text);
addRecentFile(name);
} catch (IOException e) {
// Do nothing - message already printed
}
}
}
});

// Processing for "Close..." menu item
closeItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
try {
fileManager.closeFile(textArea.getText());
textArea.setText("");
} catch (IOException e) {
// Do nothing - message already printed
}
}
});

// Processing for "Save..." menu item
saveItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
try {
fileManager.saveFile(textArea.getText());
} catch (IOException e) {
// Do nothing - message already printed
}
}
});

// Processing for "Save As..." menu item
saveAsItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (fileManager.isFileOpen()) {
String name = getFileName("Save As File", FileDialog.SAVE);
if (name != null) {
try {
fileManager.saveAsFile(name, textArea.getText());
} catch (IOException e) {
// Do nothing - message already printed
}
}
}
}
});

// Create the handler for the recent file list
menuListener = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
JMenuItem mi = (JMenuItem)(evt.getSource());
String fileName = mi.getActionCommand();
try {
String text = fileManager.openFile(fileName);
textArea.setText(text);
addRecentFile(fileName);
} catch (IOException e) {
// Do nothing - message already printed
}
}
};
}

// Add a name to the recent file list
public void addRecentFile(String fileName) {
int offset;

// Check whether this file is already in the file list
if ((offset = recentFiles.indexOf(fileName)) == -1) {
// Not present - add it at the beginning
recentFiles.insertElementAt(fileName, 0);
if (recentFiles.size() > RECENT_FILES) {
// List was full - remove the last (oldest) item
recentFiles.removeElementAt(RECENT_FILES);
}
} else {
// Already present: move this item to the front of the list
recentFiles.removeElementAt(offset);
recentFiles.insertElementAt(fileName, 0);
}


// Rebuild the file menu
buildRecentFileMenu();
}

// Build the recent file menu
public void buildRecentFileMenu() {
int size = recentFiles.size();

fileListMenu.removeAll();

for (int i = 0; i < size; i++) {
String fileName = (String)(recentFiles.elementAt(i));
JMenuItem mi = new JMenuItem(fileName);
fileListMenu.add(mi);
mi.addActionListener(menuListener);
}
}

// Get a file name
public String getFileName(String title, int mode) {
FileDialog fd = new FileDialog(this, title, mode);
fd.setFile("*.*");
fd.setDirectory(directory);

fd.setVisible(true);

String dir = fd.getDirectory();
String file = fd.getFile();
if (dir == null || file == null) {
return null;
}
directory = dir;

String separator = System.getProperty("file.separator");
if (dir.endsWith(separator)) {
return dir + file;
} else {
return dir + System.getProperty("file.separator") + file;
}
}


// Take any action needed to close the application
public void closeWindow() {
try {
fileManager.closeFile(textArea.getText());
} catch (IOException e) {
System.out.println("Failed to write data on close.");
}
System.exit(0);
}

public static void main(String[] args) {
JFrame f = new MenuExample2("Menu Example 2");
f.pack();
f.setVisible(true);
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent evt) {
MenuExample2 frame = (MenuExample2)(evt.getSource());
frame.closeWindow();
}
});
}

JMenuItem newItem;
JMenuItem openItem;
JMenuItem closeItem;
JMenuItem saveItem;
JMenuItem saveAsItem;
JMenuItem emptyListItem;
JMenu fileListMenu;
JTextArea textArea;
FileManager fileManager;
String directory = ""; // Current directory

ActionListener menuListener;

// Recently-used file list
static final int RECENT_FILES = 4;
Vector recentFiles = new Vector(RECENT_FILES);
}

package JFCBook.Chapter6;

import java.io.*;
import java.awt.Toolkit;

// Helper class to manage an open file
public class FileManager {
// Check whether a named file exists
boolean fileExists(String fileName) {
return (new File(fileName)).exists();
}

// Open a new file
void newFile(String fileName) throws IOException {
if (fileExists(fileName)) {
System.out.println("File <" + fileName + "> already exists.");
throw new IOException("File exists");
}

this.canWriteFile = true; // Assume we can write
this.fileName = fileName;
}

// Open a file
String openFile(String fileName) throws IOException, FileNotFoundException {
this.fileName = fileName;
openFile = new File(fileName);
try {
canWriteFile = openFile.canWrite();
FileInputStream fs = new FileInputStream(openFile);
long l = openFile.length();
byte[] content = new byte[(int)l];
fs.read(content);
fs.close();
return new String(content);
} catch (FileNotFoundException e) {
System.out.println("Failed to open \"" + fileName + "\".");
Toolkit.getDefaultToolkit().beep();
throw e;
} catch (IOException e) {
System.out.println("Failed to read \"" + fileName + "\".");
Toolkit.getDefaultToolkit().beep();
throw e;
}
}

// Save to the file
void saveFile(String text) throws IOException {
if (fileName != null && userWantsWrite == true && canWriteFile == true) {
openFile = new File(fileName);
try {
FileOutputStream fs = new FileOutputStream(openFile);
byte[] content = text.getBytes();
fs.write(content);
fs.close();
} catch (FileNotFoundException e) {
System.out.println("Failed to open \"" + fileName + "\" for writing.");
Toolkit.getDefaultToolkit().beep();
throw e;
} catch (IOException e) {
System.out.println("Failed to write to \"" + fileName + "\".");
Toolkit.getDefaultToolkit().beep();
throw e;
}
}
}

// Save with a different file name
void saveAsFile(String fileName, String text) throws IOException {
this.fileName = fileName;
if (userWantsWrite && canWriteFile == true) {
saveFile(text);
}
}

// Close the open file, writing data if required
void closeFile(String text) throws IOException {
if (isFileOpen()) {
// Write file content
saveFile(text);
}

fileName = null;
openFile = null;
}

// Make the file writable or not
public void setWritable(boolean writable) {
this.userWantsWrite = writable;
}

// Check whether we have an open file
boolean isFileOpen() {
return openFile != null;
}

// Check whether we can write to the file
boolean canWrite() {
return canWriteFile;
}

// Get current file name
String getFileName() {
return fileName;
}

File openFile; // File object for open file
String fileName; // Name of current open file
boolean userWantsWrite = true;
// User wants to be able to write
boolean canWriteFile = true;
// File can be written to
}

3. & 4. I got these error messages:

D:\object_code\etools>java JFCBook.Chapter6.MenuExample2
Exception occurred during event dispatching:
java.lang.UnsatisfiedLinkError: requestFocus
        at java.awt.Component.requestFocus(Component.java:2669)
        at javax.swing.plaf.basic.BasicMenuUI$ChangeHandler.validateKeyboardActi
ons(BasicMenuUI.java:380)
        at javax.swing.plaf.basic.BasicMenuUI$ChangeHandler.stateChanged(BasicMe
nuUI.java:318)
        at javax.swing.AbstractButton.fireStateChanged(AbstractButton.java:991)
        at javax.swing.AbstractButton$ButtonChangeListener.stateChanged(Abstract
Button.java:1034)
        at javax.swing.DefaultButtonModel.fireStateChanged(DefaultButtonModel.ja
va:336)
        at javax.swing.DefaultButtonModel.setSelected(DefaultButtonModel.java:22
7)
        at javax.swing.JMenu.setSelected(JMenu.java:231)
        at javax.swing.JMenu.menuSelectionChanged(JMenu.java:948)
        at javax.swing.MenuSelectionManager.setSelectedPath(MenuSelectionManager
.java:72)
        at javax.swing.MenuSelectionManager.clearSelectedPath(MenuSelectionManag
er.java:109)
        at javax.swing.plaf.basic.BasicMenuItemUI$MouseInputHandler.mouseRelease
d(BasicMenuItemUI.java:673)
        at java.awt.Component.processMouseEvent(Component.java:2355)
        at java.awt.Component.processEvent(Component.java:2200)
        at java.awt.Container.processEvent(Container.java:904)
        at java.awt.Component.dispatchEventImpl(Component.java:1809)
        at java.awt.Container.dispatchEventImpl(Container.java:949)
        at java.awt.Component.dispatchEvent(Component.java:1741)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:1739
)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:1537)

        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:1453)
        at java.awt.Container.dispatchEventImpl(Container.java:936)
        at java.awt.Window.dispatchEventImpl(Window.java:491)
        at java.awt.Component.dispatchEvent(Component.java:1741)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:79)
Exception occurred during event dispatching:
java.lang.UnsatisfiedLinkError: show
        at java.awt.Dialog.show(Dialog.java:219)
        at java.awt.Component.show(Component.java:511)
        at java.awt.Component.setVisible(Component.java:473)
        at JFCBook.Chapter6.MenuExample2.getFileName(MenuExample2.java:192)
        at JFCBook.Chapter6.MenuExample2$2.actionPerformed(MenuExample2.java:57)

        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:10
66)
        at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(Abstra
ctButton.java:1101)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel
.java:378)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:250
)
        at javax.swing.AbstractButton.doClick(AbstractButton.java:226)
        at javax.swing.plaf.basic.BasicMenuItemUI$MouseInputHandler.mouseRelease
d(BasicMenuItemUI.java:674)
        at java.awt.Component.processMouseEvent(Component.java:2355)
        at java.awt.Component.processEvent(Component.java:2200)
        at java.awt.Container.processEvent(Container.java:904)
        at java.awt.Component.dispatchEventImpl(Component.java:1809)
        at java.awt.Container.dispatchEventImpl(Container.java:949)
        at java.awt.Component.dispatchEvent(Component.java:1741)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:1739
)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:1537)

        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:1453)
        at java.awt.Container.dispatchEventImpl(Container.java:936)
        at java.awt.Window.dispatchEventImpl(Window.java:491)
        at java.awt.Component.dispatchEvent(Component.java:1741)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:79)
Exception occurred during event dispatching:
java.lang.NullPointerException: null component
        at sun.awt.windows.WGraphics.<init>(WGraphics.java:59)
        at sun.awt.windows.WComponentPeer.getGraphics(WComponentPeer.java:141)
        at java.awt.Component.getGraphics(Component.java:1175)
        at sun.awt.windows.WComponentPeer.handleEvent(WComponentPeer.java:98)

5. java -version returns java version "1.1.8", java -fullversion returns java full version "JDK1.1.8K"

6. none.
(Review ID: 56320)
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