null returned by MessageHandler.send never handled

[overheadhunter]

This method may return null:

kdewallet/src/main/java/org/freedesktop/dbus/handlers/MessageHandler.java

Lines 30 to 69 in 821e6ce

	public Object[] send(String service, String path, String iface, String method, String signature, Object... args) {
	try {
	org.freedesktop.dbus.messages.Message message = new MethodCall(
	service,
	path,
	iface,
	method, (byte) 0, signature, args);
	if (log.isTraceEnabled()) log.trace(String.valueOf(message));
	connection.sendMessage(message);
	org.freedesktop.dbus.messages.Message response = ((MethodCall) message).getReply(2000L);
	if (log.isTraceEnabled()) log.trace(String.valueOf(response));
	Object[] parameters = null;
	if (response != null) {
	parameters = response.getParameters();
	log.debug(Arrays.deepToString(parameters));
	}
	if (response instanceof org.freedesktop.dbus.errors.Error) {
	String error = response.getName();
	switch (error) {
	case "org.freedesktop.DBus.Error.NoReply":
	case "org.freedesktop.DBus.Error.UnknownMethod":
	case "org.freedesktop.dbus.exceptions.NotConnected":
	log.debug(error);
	return null;
	default:
	throw new DBusException(error);
	}
	}
	return parameters;
	} catch (DBusException e) {
	log.error("Unexpected D-Bus response:", e);
	}
	return null;
	}

But responses are always assumed to be non-null, see e.g.:

kdewallet/src/main/java/org/purejava/KDEWallet.java

Lines 110 to 114 in 821e6ce

	@Override
	public boolean isOpen(String wallet) {
	Object[] response = send("isOpen", "s", wallet);
	return (boolean) response[0];
	}

Which causes downstream uncaught NPEs, as in cryptomator/cryptomator#1866

[purejava]

Thanks for reporting this @overheadhunter. You already provided a fix in Cryptomator and I'll fix this on my side as well.