import javafx.application.Application;
import javafx.stage.Screen;
import javafx.stage.Stage;

public class CheckDPI extends Application {
    public static void main(String argv[]) {
        launch(argv);
    }

    @Override
    public void start(Stage stage) {
        for (Screen s : Screen.getScreens()) {
            System.out.println("Screen ("+s+").dpi = "+s.getDpi());
        }
        System.exit(0);
    }
}