Error calling Java Fx screens in Spring

Question

I am developing a Spring + Java Fx application, when calling the code from the main class screen, it works normally, but if I call another screen, it does not record the information in the model and gives null Pointer Exception, I tried to change the way I manage the screens and it didn’t work, keeps giving the same error... someone could help me?

This is the code of the main class, where it is working normally:

@SpringBootApplication(scanBasePackages = { "br.com.cron.folhapagamento.service",
        "br.com.folhapagamento.controller", "br.com.folhapagamento.main" })
@EntityScan(basePackages = { "br.com.folhapagamento.model" })
@EnableJpaRepositories(basePackages = { "br.com.folhapagamento.repository" })

public class FolhaDePagamentoApplication extends Application {
    private static final Logger log = 
    LoggerFactory.getLogger(FolhaDePagamentoApplication.class);

    private ConfigurableApplicationContext context;

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

    @Override
    public void init() throws Exception {
        super.init();
        SpringApplicationBuilder builder = new SpringApplicationBuilder(FolhaDePagamentoApplication.class);
        context = builder.run(getParameters().getRaw().toArray(new String[0]));

}

    @Override
    public void start(Stage primaryStage) throws Exception {
        log.info("Starting...");

        FXMLLoader loader = new 
FXMLLoader(getClass().getResource("../view/LeiAutorizativa.fxml"));
        loader.setControllerFactory(context::getBean);
        Parent root = loader.load();
        Scene scene = new Scene(root);

scene.getStylesheets().add(getClass()
       .getResource("stylesheet.css").toExternalForm());
        primaryStage.setScene(scene);
        primaryStage.setTitle("TableView App");
        primaryStage.show();

    }       
}

And here’s the class I manage the screens in, and it’s the way it’s not working, I wanted it to work normal:

private static AplicacaoUtil instancia = null;

private Stage telaAtual = null;


private AplicacaoUtil() {
    this.telaAtual = new Stage();
}

public static AplicacaoUtil getInstancia()
{
    if(instancia == null){
        instancia = new AplicacaoUtil();
    }
    return instancia;
}

public void irParaTela(String nomeTela) {
    try {
        System.out.println("Carrega o arquivo da tela desejada");
        Parent root = FXMLLoader.load(getClass().getResource("../view/".concat(nomeTela)));

        System.out.println("Cria uma nova cena para a tela e adiciona no palco (telaAtual)");
        Scene scene = new Scene(root);
        this.telaAtual.setScene(scene);

        System.out.println("Exibe o palco caso o mesmo não esteja sendo exibido");
        if(!this.telaAtual.isShowing()){
            this.telaAtual.show();
        }
    }catch(Exception e){
        System.out.println("entrou no catch");
        System.err.println("Ocorreu um erro ao tentar navegar para tela: ".concat(nomeTela).concat(" ".concat(e.getMessage())));
       //exibe uma mensagem caso a tela não tenha sido encontrada + erro original
    }
}


public void setTelaAtual(Stage telaAtual) {
    this.telaAtual = telaAtual;
}

public Stage getTelaAtual() {
    return telaAtual;
}

She manages the screens through a Singleton, and to call the screens I call the method irParaTela and step to String that will be the name of the screen, it calls, but when sending save the information in the bank it gives error.

I tried to do this also to spare the use of an auxiliary class, and I thought it would work, but it gave the same thing. :/

TelasFx telas = new TelasFx();

private static final Logger log = LoggerFactory.getLogger(FolhaDePagamentoApplication.class);

private ConfigurableApplicationContext context;

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

@Override
public void init() throws Exception {
    super.init();
    SpringApplicationBuilder builder = new SpringApplicationBuilder(FolhaDePagamentoApplication.class);
    context = builder.run(getParameters().getRaw().toArray(new String[0]));


}

@Override
public void start(Stage primaryStage) throws Exception {
    log.info("Starting...");

    FXMLLoader loader = new FXMLLoader(getClass().getResource("../view/" .concat(telas.getNomeTela())));
    loader.setControllerFactory(context::getBean);
    Parent root = loader.load();
    Scene scene = new Scene(root);
    scene.getStylesheets().add(getClass().getResource("stylesheet.css").toExternalForm());
    primaryStage.setScene(scene);
    primaryStage.setTitle("TableView App");
    primaryStage.show();

}




public void vaiParaTela() throws Exception {
    init();
    Stage primaryStage = new Stage();
    FXMLLoader loader = new FXMLLoader(getClass().getResource("../view/" .concat(telas.getNomeTela())));
    loader.setControllerFactory(context::getBean);
    Parent root = loader.load();
    Scene scene = new Scene(root);
    scene.getStylesheets().add(getClass().getResource("stylesheet.css").toExternalForm());
    primaryStage.setScene(scene);
    primaryStage.setTitle("TableView App");
    primaryStage.show();
}