Java HotSpot Virtual Machine

native Win32 sendmessage works only for some messages. (From a java application to a WndProc in C#)

I can send message like WM_CLOSE but it never send message like WM_COPYDATA (The WndProc never even receive the message)

Is there something particular with SendMessage under jni ? is there any java example of using a WM_COPYDATA to send data to something else than java? ( I tried the example somewhere in JNI and another example found on the internet and it's never working as expected since the message is never sent

Thanks,

Michel