How to choose an AWT-EventQueue thread, when there are several of them

Question

I successfully injected my own Java code in a running Oracle Forms application, using DLL Injection and some jni trickery. (Windows 7, 32 bits, Oracle Forms 11, JRE Java 8)

I am able to traverse the tree of Components and to query and set values in some basic Java objects, such as those from class oracle.forms.ui.VTextField

I am stuck when trying to simulate user click on a oracle.apps.fnd.ui.Button

I tried 2 things :

1. call the simulatePush method of the AbstractButton class
2. call the activate method of the PushButton class

(the 2 classes are in the class hierarchy for Button)

Results were identical: 1. At first, it works fine: when the button is a "Search" button, the search is done and the results are displayed. 2. Then, it immediately breaks the application, with a pop-up saying FRM-92100 Your connection to the Server was interrupted.

From there, the Application is hung.

Update: It seems that the error which cause a disconnection from the Server is:

java.lang.SecurityException: this KeyboardFocusManager is not installed in the current thread's context at java.awt.KeyboardFocusManager.checkCurrentKFMSecurity(Unknown Source) at java.awt.KeyboardFocusManager.getGlobalFocusOwner(Unknown Source) at java.awt.KeyboardFocusManager.processSynchronousLightweightTransfer(Unknown Source) at sun.awt.windows.WComponentPeer.processSynchronousLightweightTransfer(Native Method) at sun.awt.windows.WComponentPeer.requestFocus(Unknown Source) at java.awt.Component.requestFocusHelper(Unknown Source) at java.awt.Component.requestFocusHelper(Unknown Source) at java.awt.Component.requestFocus(Unknown Source) at oracle.forms.handler.UICommon.updateFocus(Unknown Source) at oracle.forms.handler.UICommon.setFVP(Unknown Source) at oracle.forms.handler.UICommon.setFVP(Unknown Source) at oracle.forms.handler.UICommon.onUpdate(Unknown Source) at oracle.forms.handler.ComponentItem.onUpdate(Unknown Source) at oracle.forms.handler.JavaContainer.onUpdate(Unknown Source) at oracle.forms.handler.UICommon.onUpdate(Unknown Source) at oracle.forms.engine.Runform.onUpdateHandler(Unknown Source) at oracle.forms.engine.Runform.processMessage(Unknown Source) at oracle.forms.engine.Runform.processSet(Unknown Source) at oracle.forms.engine.Runform.onMessageReal(Unknown Source) at oracle.forms.engine.Runform.onMessage(Unknown Source) at oracle.forms.engine.Runform.processEventEnd(Unknown Source) at oracle.ewt.lwAWT.LWComponent.redispatchEvent(Unknown Source) at oracle.ewt.lwAWT.LWComponent.processEvent(Unknown Source) at oracle.ewt.button.PushButton.activate(Unknown Source) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at CustomAWT.run(CustomAWT.java:34) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$400(Unknown Source) at java.awt.EventQueue$2.run(Unknown Source) at java.awt.EventQueue$2.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)

My code is here: CustomAWT.run(CustomAWT.java:34) and is called with invokeLater. Problem is probably: when calling the oracle.ewt.button.PushButton.activate method, I am NOT in the right EDT.

Using "List Threads" in the Java Console, I got:

Dump thread list ...
Group main,ac=30,agc=2,pri=10
    main,5,alive
    traceMsgQueueThread,5,alive,daemon
    Timer-0,5,alive
    Java Plug-In Pipe Worker Thread (Client-Side),5,alive,daemon
    AWT-Shutdown,5,alive
    AWT-Windows,6,alive,daemon
    AWT-EventQueue-0,6,alive
    SysExecutionTheadCreator,5,alive,daemon
    CacheMemoryCleanUpThread,5,alive,daemon
    CacheCleanUpThread,5,alive,daemon
    Browser Side Object Cleanup Thread,5,alive
    JVM[id=0]-Heartbeat,5,alive,daemon
    Windows Tray Icon Thread,5,alive
    Thread-13,5,alive
Group Plugin Thread Group,ac=3,agc=0,pri=10
    AWT-EventQueue-1,6,alive
    TimerQueue,5,alive,daemon
    ConsoleWriterThread,6,alive,daemon
Group http://xxxx.xxxx.xxxxx.xx:8001/OA_JAVA/-threadGroup,ac=13,agc=0,pri=4
    Applet 1 LiveConnect Worker Thread,4,alive
    AWT-EventQueue-2,4,alive
    thread applet-oracle/apps/fnd/formsClient/FormsLauncher.class-1,4,alive
    Applet 2 LiveConnect Worker Thread,4,alive
    thread applet-oracle.forms.engine.Main-2,4,alive
    Forms-StreamMessageReader,4,alive
    Forms-StreamMessageWriter,4,alive
    HeartBeat,4,alive
    Busy indicator,1,alive,daemon
    TaskScheduler timer,4,alive
    CursorIdler,4,alive
    Thread-14,4,alive
    Flush Queue,4,alive
Done.

So, there is THREE AWT-EventQueue threads... Question is now: How to query/retrieve the right one, and how to make the Runnable passed to invokeLater to run in the "Good Thread" (I guess that the good one is the last one (AWT-EventQueue-2)

Answer 1

To get the correct EDT thread regardless of your thread group, you can use SunToolkit.targetToAppContext(Object target), and for the parameter you can feed it the AWT component you intend to act on. Example source.

Then get the EventQueue using EventQueue eq = SunToolkit.getSystemEventQueueImplPP(appContext);

Finally, create a new InvocationEvent with your runnable and call postEvent on the EQ.