Hi Mark,
The default look and feel is Metal on all OS except for macOS where the
default is Aqua.
You can modify the default look and feel using the the
|swing.defaultlaf| property, and it works for me as expected. The
default look and feel of an application is initialised to the class in
the |swing.defaultlaf| property.
I ran a simple Java program on Windows:
java DefaultLookAndFeel.java
[*The Java(tm) Look and Feel* - javax.swing.plaf.metal.MetalLookAndFeel]
com.sun.java.swing.plaf.windows.WindowsLookAndFeel
javax.swing.plaf.metal.MetalLookAndFeel
java
-Dswing.defaultlaf=com.sun.java.swing.plaf.windows.WindowsLookAndFeel
DefaultLookAndFeel.java
[*The Microsoft Windows Look and Feel* -
com.sun.java.swing.plaf.windows.WindowsLookAndFeel]
com.sun.java.swing.plaf.windows.WindowsLookAndFeel
javax.swing.plaf.metal.MetalLookAndFeel
The |swing.defaultlaf| property is documented and is used in the
tutorial How to Set the Look and Feel
<https://docs.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html>,
specifically the section Specifying the Look and Feel: Command Line
<https://docs.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html#commandLine>
has two examples how to modify the default look and feel.
If set the value to a class that doesn't exist, I'll get an exception:
java -Dswing.defaultlaf=NimbusLookAndFeel DefaultLookAndFeel.java
Exception in thread "main" java.lang.Error: Cannot load
NimbusLookAndFeel at
java.desktop/javax.swing.UIManager.initializeDefaultLAF(UIManager.java:1390)
at java.desktop/javax.swing.UIManager.initialize(UIManager.java:1501) at
java.desktop/javax.swing.UIManager.maybeInitialize(UIManager.java:1467)
at java.desktop/javax.swing.UIManager.getLookAndFeel(UIManager.java:492)
at DefaultLookAndFeel.main(DefaultLookAndFeel.java:5)
You can use these line numbers to study how default look and feel is
initialised.
Please note the client-libs-dev mailing list is not a support forum, it
is place to discuss /development of client libraries/.
--
Regards,
Alexey
On 2025-06-19 19:04, Ludwig, Mark wrote:
Greetings,
We are in the process of (finally) completing a migration from
AWT-based windows and dialogs to Swing-based that was started in the
1990s.
Testing the external Swing controls on Linux, we find nothing seems to
happen as a result of setting the “swing.defaultlaf” System Property.
This is documented in multiple places – at least the
javax.swing.UIManager doc, and the *How to Set the Look and Feel*
tutorial (and is mentioned in
https://bugs.openjdk.org/browse/JDK-8159164).
We find the “swing.systemlaf” System Property is effective in changing
the returned value from UIManager.getSystemLookAndFeelClassName(), but
does not by itself change the look-and-feel -- only with something
like
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()),
which is documented.
We would appreciate clarity on this discrepancy regarding the
“default” look-and-feel for Swing on Linux.
Thanks,
Mark Ludwig
The source of the sample app:
|import javax.swing.UIManager; public class DefaultLookAndFeel { public
static void main(String[] args) {
System.out.println(UIManager.getLookAndFeel());
System.out.println(UIManager.getSystemLookAndFeelClassName());
System.out.println(UIManager.getCrossPlatformLookAndFeelClassName()); } }|
