final Map<String, String[]> map = new TreeMap<>();

    private void fillMap() {
        Properties prop = new Properties();
        this.getClass().getResourceAsStream("C:/Users/Emir/OneDrive/Documents/NewOne/LibraryManagementSystem/src/main/java/companyProperty");
        prop.forEach((key, value) -> map.put(key.toString(), value.toString().split(",")));
        map.forEach((k, v) -> System.out.println(k + ": " + Arrays.toString(v)));
    }

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) {
        fillMap();

        stage.setTitle("ComboBoxSample");
        Scene scene = new Scene(new Group());
        final ComboBox<String> company = new ComboBox<>();
        company.getItems().addAll(new ArrayList<>(map.keySet()));

        final ComboBox<String> priorityComboBox = new ComboBox<>();
        priorityComboBox.getItems().addAll(new ArrayList<>(map.keySet()));

        /*company.setCellFactory(lv -> new ListCell<>() {
            public void updateItem(String item, boolean empty) {
                super.updateItem(item, empty);
                if (empty) {
                    setText(null);
                } else {
                    setText(item);
                    switch (item) {
                        case "Automotive":
                        case "Engineering, various":
                        case "Electronics":
                        case "Pharmaceuticals":
                        case "Aerospace & Defense":
                        case "Chemicals":
                        case "Food & Beverages":
                        case "Steel":
                            setOpacity(0.5);
                            setDisable(true);
                            break;
                        default:
                            setOpacity(2);
                            setDisable(false);
                    }
                }
            }
        });

        company.valueProperty().addListener((ov, t, t1) -> {
            char firstIDLetter = t1.toUpperCase().charAt(0);
            char secondIDLetter = t1.toUpperCase().charAt(t1.length() - 1);
            *//* System.out.println(ov);*//*
            *//*System.out.println(t); Previous value *//*
            System.out.printf("%s%s", firstIDLetter, secondIDLetter);
        });*/
        priorityComboBox.setValue("Normal");
        company.setValue("Hydrotec Military Vehicles");
        GridPane grid = new GridPane();
        grid.setVgap(4);
        grid.setHgap(10);
        grid.setPadding(new Insets(5, 5, 5, 5));
        grid.add(new Label("Companies: "), 0, 0);
        grid.add(company, 1, 0);
        grid.add(new Label("Products: "), 0, 1);
        grid.add(priorityComboBox, 1, 1);
        /*grid.add(new Label("Subject: "), 0, 1);
        grid.add(subject, 1, 1, 3, 1);*/
        /* grid.add(text, 0, 2, 4, 1);*/
        /* grid.add(button, 0, 3);*/
        grid.setVgap(15);
        /*grid.add(notification, 1, 3, 3, 1);*/

        Group root = (Group) scene.getRoot();
        root.getChildren().add(grid);
        stage.setScene(scene);
        stage.show();

    }
}