In EditingContextEventProcessor, we have:

Future<?> future = this.executorService.submit(() -> this.doHandle(payloadSink, input));
try {
  // Block until the event has been processed
  future.get();
} catch (...) {
  //
}

The future.get() call has no timeout, so if for some reason the handler does not terminate (infinite loop, deadlock...), the http handler thread which executes EditingContextEventProcessor stays blocked indefinitely. If enough http requests trigger the offending handler, we can get to a point where enough threads are holding server resources (e.g. JDBC connections) that new requests can not be handled at all.

We can't do much to prevent buggy event handlers to run forever, but we can probably avoid the blocking to affect the EditingContextEventProcessor's thread.