I was testing my application on Linux. The Java version is
[joseluisbz@centos ~]$ javac -version
javac 1.8.0_251
[joseluisbz@centos ~]$ java -version
}java version "1.8.0_251"
Java(TM) SE Runtime Environment (build 1.8.0_251-b08)
Java HotSpot(TM) 64-Bit Server VM (build 25.251-b08, mixed mode)
[joseluisbz@centos ~]$
Checking DISPLAY variable
[joseluisbz@centos ~]$ printenv | grep DISPLAY
DISPLAY=:0
WAYLAND_DISPLAY=wayland-0
[joseluisbz@centos ~]$
[joseluisbz@centos ~]$ sudo printenv | grep DISPLAY
DISPLAY=:0
[joseluisbz@centos ~]$
[joseluisbz@centos ~]$ sudo -Hiu root env | grep DISPLAY
DISPLAY=:0
[joseluisbz@centos ~]$ sudo -Hiu joseluisbz env | grep DISPLAY
DISPLAY=:0
[joseluisbz@centos ~]$
Here the code:
private static final String OS = System.getProperty("os.name").toLowerCase();
public static Boolean isMacOS() {
return (OS.contains("mac") || OS.contains("darwin"));
}
public static Boolean isLinux() {
return (OS.contains("nix") || OS.contains("nux") || OS.contains("aix"));
}
public static Boolean isWindows() {
return (OS.contains("windows"));
}
public static void main(String args[]) {
System.out.println("");
String osName = System.getProperty("os.name");
String display = System.getenv("DISPLAY");
System.out.println("System.getProperty(\"os.name\"):" + System.getProperty("os.name"));
System.out.println("System.getenv(\"DISPLAY\"):" + System.getenv("DISPLAY"));
Boolean headless = ("Linux".equals(osName) ||
"SunOS".equals(osName) ||
"FreeBSD".equals(osName) ||
"NetBSD".equals(osName) ||
"OpenBSD".equals(osName) ||
"AIX".equals(osName)) &&
(display == null || display.trim().isEmpty());
System.out.println("headless:" + headless);
System.out.println("");
for (UIManager.LookAndFeelInfo lafInfo : UIManager.getInstalledLookAndFeels()) {
System.out.println("lafInfo.getName():" + lafInfo.getName()
+ "\tinfo.getClassName():" + lafInfo.getClassName());
}
System.out.println("LookAndFeelInfo printed all\n");
try {
// UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
// UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
// UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
// javax.swing.UIManager.setLookAndFeel("com.apple.laf.AquaLookAndFeel");
// javax.swing.UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel");
// javax.swing.UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
if (isMacOS()) {
System.setProperty("apple.awt.brushMetalLook", "true");
System.setProperty("apple.laf.useScreenMenuBar", "true");
System.setProperty("apple.awt.application.name", "FlexibleFileFinder");
System.setProperty("apple.awt.graphics.EnableQ2DX", "true");
}
System.out.println("OS:" + OS);
if (isMacOS()) {
UIManager.setLookAndFeel("com.apple.laf.AquaLookAndFeel");
} else if (isLinux()) {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel");
} else if (isWindows()) {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
} else {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}
System.out.println("UIManager.getLookAndFeel():" + UIManager.getLookAndFeel() + "\n");
} catch (ClassNotFoundException | InstantiationException
| IllegalAccessException | javax.swing.UnsupportedLookAndFeelException ex) {
LOGGER.log(Level.SEVERE, null, ex);
}
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
RecursiveFolderAndFiles recursiveFolderAndFiles = new RecursiveFolderAndFiles();
MainMenu mainMenu = new MainMenu(recursiveFolderAndFiles);
MethodGUI.enableOSXFullscreen(recursiveFolderAndFiles);
MethodGUI.requestToggleFullScreen(recursiveFolderAndFiles);
recursiveFolderAndFiles.setJMenuBar(mainMenu.getMainMenuBar());
recursiveFolderAndFiles.setVisible(true);
}
});
}
}
I was running my Java app in CentOS 8.
[joseluisbz@centos ~]$ java -jar "/home/joseluisbz/Documents/FlexibleFileFinder-Full/dist/FlexibleFileFinder.jar"
System.getProperty("os.name"):Linux
System.getenv("DISPLAY")::0
headless:false
lafInfo.getName():Metal info.getClassName():javax.swing.plaf.metal.MetalLookAndFeel
lafInfo.getName():Nimbus info.getClassName():javax.swing.plaf.nimbus.NimbusLookAndFeel
lafInfo.getName():CDE/Motif info.getClassName():com.sun.java.swing.plaf.motif.MotifLookAndFeel
lafInfo.getName():GTK+ info.getClassName():com.sun.java.swing.plaf.gtk.GTKLookAndFeel
LookAndFeelInfo printed all
OS:linux
UIManager.getLookAndFeel():[GTK look and feel - com.sun.java.swing.plaf.gtk.GTKLookAndFeel]
Running with sudo
[joseluisbz@centos ~]$ sudo java -jar "/home/joseluisbz/Documents/FlexibleFileFinder-Full/dist/FlexibleFileFinder.jar"
System.getProperty("os.name"):Linux
System.getenv("DISPLAY")::0
headless:false
No protocol specified
Exception in thread "main" java.awt.AWTError: Can't connect to X11 window server using ':0' as the value of the DISPLAY variable.
at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method)
at sun.awt.X11GraphicsEnvironment.access$200(X11GraphicsEnvironment.java:65)
at sun.awt.X11GraphicsEnvironment$1.run(X11GraphicsEnvironment.java:115)
at java.security.AccessController.doPrivileged(Native Method)
at sun.awt.X11GraphicsEnvironment.<clinit>(X11GraphicsEnvironment.java:74)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at java.awt.GraphicsEnvironment.createGE(GraphicsEnvironment.java:103)
at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:82)
at sun.awt.X11.XToolkit.<clinit>(XToolkit.java:132)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at java.awt.Toolkit$2.run(Toolkit.java:860)
at java.awt.Toolkit$2.run(Toolkit.java:855)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.Toolkit.getDefaultToolkit(Toolkit.java:854)
at sun.swing.SwingUtilities2.getSystemMnemonicKeyMask(SwingUtilities2.java:2031)
at javax.swing.plaf.basic.BasicLookAndFeel.initComponentDefaults(BasicLookAndFeel.java:1158)
at javax.swing.plaf.metal.MetalLookAndFeel.initComponentDefaults(MetalLookAndFeel.java:431)
at javax.swing.plaf.basic.BasicLookAndFeel.getDefaults(BasicLookAndFeel.java:148)
at javax.swing.plaf.metal.MetalLookAndFeel.getDefaults(MetalLookAndFeel.java:1577)
at javax.swing.UIManager.setLookAndFeel(UIManager.java:539)
at javax.swing.UIManager.setLookAndFeel(UIManager.java:579)
at javax.swing.UIManager.initializeDefaultLAF(UIManager.java:1349)
at javax.swing.UIManager.initialize(UIManager.java:1459)
at javax.swing.UIManager.maybeInitialize(UIManager.java:1426)
at javax.swing.UIManager.getInstalledLookAndFeels(UIManager.java:419)
at org.bz.filefinder.MainClass.main(MainClass.java:56)
[joseluisbz@centos ~]$
The line 56 is
for (UIManager.LookAndFeelInfo lafInfo : UIManager.getInstalledLookAndFeels()) {
Trying again with sudo and -Djava.awt.headless=true
[joseluisbz@centos ~]$ sudo java -Djava.awt.headless=true -jar "/home/joseluisbz/Documents/FlexibleFileFinder-Full/dist/FlexibleFileFinder.jar"
System.getProperty("os.name"):Linux
System.getenv("DISPLAY")::0
headless:false
lafInfo.getName():Metal info.getClassName():javax.swing.plaf.metal.MetalLookAndFeel
lafInfo.getName():Nimbus info.getClassName():javax.swing.plaf.nimbus.NimbusLookAndFeel
lafInfo.getName():CDE/Motif info.getClassName():com.sun.java.swing.plaf.motif.MotifLookAndFeel
lafInfo.getName():GTK+ info.getClassName():com.sun.java.swing.plaf.gtk.GTKLookAndFeel
LookAndFeelInfo printed all
OS:linux
Jul 04, 2020 5:08:17 PM org.bz.filefinder.MainClass main
SEVERE: null
javax.swing.UnsupportedLookAndFeelException: [GTK look and feel - com.sun.java.swing.plaf.gtk.GTKLookAndFeel] not supported on this platform
at javax.swing.UIManager.setLookAndFeel(UIManager.java:526)
at javax.swing.UIManager.setLookAndFeel(UIManager.java:583)
at org.bz.filefinder.MainClass.main(MainClass.java:82)
Exception in thread "AWT-EventQueue-0" java.awt.HeadlessException
at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:204)
at java.awt.Window.<init>(Window.java:536)
at java.awt.Frame.<init>(Frame.java:420)
at java.awt.Frame.<init>(Frame.java:385)
at javax.swing.JFrame.<init>(JFrame.java:189)
at org.bz.filefinder.RecursiveFolderAndFiles.<init>(RecursiveFolderAndFiles.java:43)
at org.bz.filefinder.MainClass$1.run(MainClass.java:97)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
[joseluisbz@centos ~]$
The line 82 is
UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel");
I was testing with
UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
and they failed as well.!
Why works for non root or sudo user, but it fails with sudo or root?
NOTE:
code of java.awt.GraphicsEnvironment
static void checkHeadless() throws HeadlessException {
if (isHeadless()) { //LINE 203!!!
throw new HeadlessException();
}
}
public static boolean isHeadless() {
return getHeadlessProperty();
}
private static boolean getHeadlessProperty() {
if (headless == null) {
AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
String nm = System.getProperty("java.awt.headless");
if (nm == null) {
/* No need to ask for DISPLAY when run in a browser */
if (System.getProperty("javaplugin.version") != null) {
headless = defaultHeadless = Boolean.FALSE;
} else {
String osName = System.getProperty("os.name");
if (osName.contains("OS X") && "sun.awt.HToolkit".equals(
System.getProperty("awt.toolkit")))
{
headless = defaultHeadless = Boolean.TRUE;
} else {
final String display = System.getenv("DISPLAY");
headless = defaultHeadless =
("Linux".equals(osName) ||
"SunOS".equals(osName) ||
"FreeBSD".equals(osName) ||
"NetBSD".equals(osName) ||
"OpenBSD".equals(osName) ||
"AIX".equals(osName)) &&
(display == null || display.trim().isEmpty());
}
}
} else {
headless = Boolean.valueOf(nm);
}
return null;
});
}
return headless;
}
NOTE 1:
[joseluisbz@centos ~]$ sudo xterm
[sudo] password for joseluisbz:
sudo: xterm: command not found
[joseluisbz@centos ~]$ xterm
bash: xterm: command not found...
Install package 'xterm' to provide command 'xterm'? [N/y] y
* Waiting in queue...
* Loading list of packages....
The following packages have to be installed:
xorg-x11-fonts-misc-7.5-19.el8.noarch misc bitmap fonts for the X Window System
xterm-331-1.el8.x86_64 Terminal emulator for the X Window System
xterm-resize-331-1.el8.x86_64 Set environment and terminal settings to current window size
Proceed with changes? [N/y] y
* Waiting in queue...
* Waiting for authentication...
* Waiting in queue...
* Downloading packages...
* Requesting data...
* Testing changes...
* Installing packages...
[joseluisbz@centos ~]$
NOTE 2
# cd /etc/X11/ && Xorg -configure
# X -config -retro /root/xorg.conf.new
# X -config -retro /etc/X11/xorg.conf
# startx
Working with root user.
[joseluisbz@centos ~]$ sudo startx
xauth: file /root/.serverauth.3620 does not exist
X.Org X Server 1.20.6
X Protocol Version 11, Revision 0
Build Operating System: 4.19.34-300.el7.x86_64
Current Operating System: Linux centos.joseluisbz 4.18.0-193.6.3.el8_2.x86_64 #1 SMP Wed Jun 10 11:09:32 UTC 2020 x86_64
Kernel command line: BOOT_IMAGE=(hd1,gpt7)/vmlinuz-4.18.0-193.6.3.el8_2.x86_64 root=UUID=8e22004f-7639-4530-a2db-df80df04aa6d ro crashkernel=auto resume=UUID=8c61ca21-ec17-4aed-b695-c83c373f7ff0 rhgb quiet
Build Date: 24 April 2020 02:49:29AM
Build ID: xorg-x11-server 1.20.6-3.el8
Current version of pixman: 0.38.4
Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.2.log", Time: Sat Jul 4 18:03:05 2020
(==) Using config directory: "/etc/X11/xorg.conf.d"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
(II) modeset(0): Initializing kms color map for depth 24, 8 bpc.
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Internal error: Could not resolve keysym XF86MonBrightnessCycle
> Internal error: Could not resolve keysym XF86RotationLockToggle
Errors from xkbcomp are not fatal to the X server
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Internal error: Could not resolve keysym XF86MonBrightnessCycle
> Internal error: Could not resolve keysym XF86RotationLockToggle
Errors from xkbcomp are not fatal to the X server
Failed to import environment: Process org.freedesktop.systemd1 exited with status 1
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Internal error: Could not resolve keysym XF86MonBrightnessCycle
> Internal error: Could not resolve keysym XF86RotationLockToggle
Errors from xkbcomp are not fatal to the X server
xinit: connection to X server lost
waiting for X server to shut down (II) Server terminated successfully (0). Closing log file.
[joseluisbz@centos ~]$
When root is logged
[root@centos ~]# whoami
root
[root@centos ~]# pwd
/root
[root@centos ~]# java -jar "/home/joseluisbz/Documents/FlexibleFileFinder-Full/dist/FlexibleFileFinder.jar"
System.getProperty("os.name"):Linux
System.getenv("DISPLAY")::2
System.getProperty("java.awt.headless"):null
headless:false
lafInfo.getName():Metal info.getClassName():javax.swing.plaf.metal.MetalLookAndFeel
lafInfo.getName():Nimbus info.getClassName():javax.swing.plaf.nimbus.NimbusLookAndFeel
lafInfo.getName():CDE/Motif info.getClassName():com.sun.java.swing.plaf.motif.MotifLookAndFeel
lafInfo.getName():GTK+ info.getClassName():com.sun.java.swing.plaf.gtk.GTKLookAndFeel
LookAndFeelInfo printed all
OS:linux
UIManager.getLookAndFeel():[GTK look and feel - com.sun.java.swing.plaf.gtk.GTKLookAndFeel]
JFrame.class.isAssignableFrom(RecursiveFolderAndFiles.class):true
RecursiveFolderAndFiles.class.isAssignableFrom(OneSearch.class):false
RulerPanel.class.isAssignableFrom(OneSearch.class):false
RulerPanel.class.isAssignableFrom(JPanel.class):false
JPanel.class.isAssignableFrom(RulerPanel.class):true
Jul 04, 2020 6:41:10 PM org.bz.filefinder.RecursiveFolderAndFiles <init>
INFO: System.getProperty("user.dir"): /root
Jul 04, 2020 6:41:10 PM org.bz.filefinder.RecursiveFolderAndFiles <init>
INFO: System.getProperty("user.home"): /root
NOTE 3
[joseluisbz@centos ~]$ sudo xterm
No protocol specified
Warning: This program is an suid-root program or is being run by the root user.
The full text of the error or warning message cannot be safely formatted
in this environment. You may get a more descriptive message by running the
program as a non-root user or by removing the suid bit on the executable.
xterm: Xt error: Can't open display: %s
[joseluisbz@centos ~]$
NOTE 4:
sudo dnf install xterm
sudo dnf install xorg-x11-server-utils
sudo dnf install xorg-x11-apps
sudo dnf groupinstall "legacy-x"
