Description Jiri Sliva 2010-10-19 09:51:43 EDT

Build Identifier: I20090611-1540

Hello,

We have SWT-based applet (uses SWT_AWT bridge) which we want to starts via webstart.
Problems occurs when we try start second instance of that applet (in same browser).

In last step of applet's UI initialization - on first call of display.readAndDispatch() is raised Invalid thread access exception.

Line 2 on following code ..

1.    while (!shell.isDisposed()) {
2.      if (!display.readAndDispatch()) {
3.        display.sleep();
4.      }
5.    }
6.    display.dispose();


Some facts:
- Each applet instance has own shell and display and runs in own threads.
- Same behavior in Mozilla Firefox and MS IE.
- Exception isn't raised when applet is started WITHOUT Webstart/JNLP (but in classic approach).
- Exception isn't raised when applet is started directly by javaws executable. I mean without browser java plugin (e.g. opening jnlp file from windows explorer). In that case have each applet own JVM.
- Usage of pack200 doesn't have any impact to this issue.

When more instances of applet is started by webstart from browser then some that applets are running in same JVM but in different "sandboxes" (different classloaders?) - so it looks that applets are separated but there still remains some sharing in SWT internals.

If browser will start unique JVM for each webstart applet depends on browser. Firefox uses all time only one JVM, Internet Explorer starts more instances of JVM (e.g. 2 JVMs for 5 applets).

Exception details:

Java Plug-in 1.6.0_21
Using JRE version 1.6.0_21-b07 Java HotSpot(TM) Client VM
..
..
Wed Oct 06 11:37:10 CEST 2010: TestApplet - Started
Wed Oct 06 11:37:10 CEST 2010: TestApplet - Initialized. Start UI Loop.
Exception in thread "UI" org.eclipse.swt.SWTException: Invalid thread access
	at org.eclipse.swt.SWT.error(SWT.java:3884)
	at org.eclipse.swt.SWT.error(SWT.java:3799)
	at org.eclipse.swt.SWT.error(SWT.java:3770)
	at org.eclipse.swt.widgets.Widget.error(Widget.java:463)
	at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:355)
	at org.eclipse.swt.widgets.Shell.getShell(Shell.java:1080)
	at org.eclipse.swt.widgets.Control.sendFocusEvent(Control.java:2568)
	at org.eclipse.swt.widgets.Widget.wmSetFocus(Widget.java:2282)
	at org.eclipse.swt.widgets.Control.WM_SETFOCUS(Control.java:4573)
	at org.eclipse.swt.widgets.Canvas.WM_SETFOCUS(Canvas.java:449)
	at org.eclipse.swt.widgets.Decorations.WM_SETFOCUS(Decorations.java:1728)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:4014)
	at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:342)
	at org.eclipse.swt.widgets.Decorations.windowProc(Decorations.java:1578)
	at org.eclipse.swt.widgets.Shell.windowProc(Shell.java:2010)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:4589)
	at org.eclipse.swt.internal.win32.OS.SetFocus(Native Method)
	at org.eclipse.swt.widgets.Control.forceFocus(Control.java:978)
	at org.eclipse.swt.widgets.Control.setFocus(Control.java:2965)
	at org.eclipse.swt.widgets.Composite.setFocus(Composite.java:928)
	at org.eclipse.swt.widgets.Shell.open(Shell.java:1220)
	at example.TestApplet.run(TestApplet.java:65)
	at java.lang.Thread.run(Unknown Source)


I can provide war archive with mentioned testing applet and JNLP files.
http://snadzitra.net/tmp/webstart/example-swt-webstart-applet.zip

We were asking in Eclipse Community Forum, but without response.
http://www.eclipse.org/forums/index.php?t=msg&th=197936&start=0&S=a8a75afdb90d8a39fc8160e67381ea9c

Thanks in advance.

Kind regards,
-Jiri Sliva


Reproducible: Always

Steps to Reproduce:
1. Download and build (or use prepared war) following testing applet  http://snadzitra.net/tmp/webstart/example-swt-webstart-applet.zip
2. Deploy it to some webserver (we tested it on apache-tomcat-6.0.26.
3. Start two instances of applet. 
4. In Java Console you should see mentioned exception.