<Swing Dev> RFR: 8198649 : Switch AWT/Swing's default GTK version to 3

[Prasanta Sadhukhan]

+1

Regards
Prasanta
On 3/16/2018 11:04 PM, Phil Race wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8198649
> Webrev: http://cr.openjdk.java.net/~prr/8198649/
>
> This is a very small change to switch the default GTK library loaded
> from GTK 2.2 to GTK 3.
>
> Both are supported as of JDK 9 but it still defaults to 2.2 and you use
> jdk.gtk.version=3 to switch.
>
> Since only one of these can be loaded a switch is necessary in case
> auto-detect fails or JDK get to load its version first, but making 
> GTK3 load
> by default will help with SWT interop as shown here  where we load
> Swing's GTK L+F followed by SWT
>
> ---
> import javax.swing.UIManager;
> import org.eclipse.swt.widgets.Display;
>
> public class SWT_Swing {
>  public static void main(String[] args) throws Exception {
> UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
>         Display display = new Display();
>  }
> }
>
> -- 
>
> /jdk9/bin/java -Djdk.gtk.verbose=true  -cp swt.jar:. SWT_Swing Looking 
> for GTK2 library...
> GTK2 library loaded.
>
> (java:21435): GLib-GObject-WARNING **: cannot register existing type 
> 'GdkDisplayManager'
>
> (java:21435): GLib-CRITICAL **: g_once_init_leave: assertion 'result 
> != 0' failed
>
> (java:21435): GLib-GObject-CRITICAL **: g_object_new: assertion 
> 'G_TYPE_IS_OBJECT (object_type)' failed
>
> ---
>
> As you can see SWT now cannot work since JDK loaded GTK 2.2 by default
> and unlike JDK SWT has no detection code or automatic fall back
>
> But with the proposed change we get no error :
> ~/jdk-11/build/linux-x86_64-normal-server-release/jdk/bin/java 
> -Djdk.gtk.verbose=true  -cp swt.jar:. SWT_Swing
> Looking for GTK3 library...
> GTK3 library loaded.
>
> Granted, the reverse problem would happen for apps that depend on GTK 2.2
> but that is looking backwards ..
>
> I have also run the SwingSet2 demo in the various cases and it is fine.
>
> We expect to make the same switch for JavaFX.
>
> -phil.
>
>
>