It would be useful to have a method available to an application that would cause a breakpoint or other event to occur unconditionally in a debugger. Today, the most an application can do is throw an uncaught exception and hope that the debugger is configured to stop on uncaught exceptions and that there is no implicit catch of the exception somewhere above in the call stack (see the documentation of ExceptionEvent.catchLocation for details).

From the application's point of view, perhaps there can be a method in the core libraries, e.g. java.lang.System.DebugBreak(), that can be called to trigger the event. From the debugger's point of view, perhaps a new (unmaskable?) event can be created called ApplicationGeneratedEvent which suspends all application threads.