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Themes for NetBeans Platform Applications

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Today I found out, from David Strupl on the NetBeans Platform mailing list, that NetBeans Platform applications can have themes/skins defined, via XML files. That means that I hadn't read the Main class of the NetBeans Platform before, where I would have found the following method:

 public static void initUICustomizations() {
  if (!CLIOptions.isGui ()) {

  URL themeURL = null;
  boolean wantTheme = Boolean.getBoolean ("netbeans.useTheme") ||
      CLIOptions.uiClass != null && CLIOptions.uiClass.getName().indexOf("MetalLookAndFeel") >= 0;

  try {
      if (wantTheme) {
          //Put a couple things into UIDefaults for the plaf library to process if it wants
           FileObject fo = FileUtil.getConfigFile("themes.xml"); //NOI18N
           if (fo == null) {            
                // File on SFS failed --> try to load from a jar from path
                // /org/netbeans/core/startup/resources/themes.xml
                try {
                    themeURL = new URL("nbresloc:/org/netbeans/core/startup/resources/themes.xml"); //NOI18N
                    // check whether the file is there:
                } catch (IOException ex) {
                    themeURL = null;
           } else {
                try {
                    themeURL = fo.getURL();
                } catch (FileStateInvalidException fsie) {
                    //do nothing
  } finally {
      CoreBridge.getDefault ().initializePlaf(CLIOptions.uiClass, CLIOptions.getFontSize(), themeURL);
  if (CLIOptions.getFontSize() > 0 && "GTK".equals(UIManager.getLookAndFeel().getID())) { //NOI18N
  StartLog.logProgress("Fonts updated"); // NOI18N

So, you can define a "themes.xml" file, in certain places, which the NetBeans Platform will then pick up and apply to the application. If you're not using Metal, then you need to provide a special setting to enable themes support.

Here's where I define my "themes.xml" file:

And all the definitions of the content of the file can be found here:

Some sample themes are included, though they're not necessarily aesthetically pleasing, you can definitely see that something different happened to the application:

Where might themes be useful? Well, here's a themes file that could be pretty handy...

<themeset active="tableRows">

    <theme name="tableRows">
        <color key="Table.background1" r="170" g="144" b="119"/>
        <color key="Table.selectionBackground1" r="190" g="170" b="140"/>
        <color key="Table.background2" r="250" g="240" b="210"/>
        <color key="Table.selectionBackground2" r="198" g="183" b="157"/>


...since it results in the table rows below having alternate colors:

However, if you were using Nimbus, you wouldn't need the above theme, since Nimbus shows alternate colors out of the box:

In the case of Nimbus, and all other non-Metal look-and-feels, you need to (as can be read in the code at the top of this article) set "-J-Dnetbeans.useTheme=true" in the "" of the application, if you want to use a themes file:

run.args.extra=--laf -J-Dnetbeans.useTheme=true

The above will then enable a Nimbus look-and-feel to have a limited subset of theme definitions being available to it, such as these for enlarging the font:

Pretty cool that themes support is available and that it is fairly easy to apply them in this way.



Published at DZone with permission of its author, Geertjan Wielenga.


Tim Sparg replied on Wed, 2010/04/21 - 3:27am

Is it possible to change the look and feel of the platform at runtime?

I tried


 but it didnt seem to work for me, is there another way to do it?

Robert Piesnikowski replied on Thu, 2010/04/22 - 11:20am

Hello Sparg.

I used changing Look & Feel at runtime but only in Swing application. Neverheless if you use 



You have to remeber to revalidate all controls in JFrame. To do this you need to have reference to your JFrame window and after setting new L&F you simply revalidate all inside window. 





Bu Gu replied on Sun, 2010/08/01 - 1:49am

thanx,the theme is very beautiful!

Matt Coleman replied on Fri, 2012/06/22 - 1:58am

wonderfully made usual good work!   buffalo web design

Mateo Gomez replied on Thu, 2012/08/09 - 12:39am in response to: Robert Piesnikowski

hey,Robert..i followed this and it worked...thanks!

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