import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.StrokeLineJoin;
import javafx.stage.Stage;

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

    Rectangle makeRect(int i, StrokeLineJoin join) {
        Rectangle r = new Rectangle(i*100+20, 20, 60, 60);
        r.setFill(null);
        r.setStroke(Color.BLUE);
        r.setStrokeWidth(20);
        r.setStrokeLineJoin(join);
        return r;
    }

    @Override
    public void start(Stage stage) {
        Group root = new Group(
            makeRect(0, StrokeLineJoin.BEVEL),
            makeRect(1, StrokeLineJoin.MITER),
            makeRect(2, StrokeLineJoin.ROUND)
        );
        
        Scene scene = new Scene(root, 300, 100);
        stage.setScene(scene);
        stage.show();
    }
}