taskException.java

...
catch (Exception e) {
	// e.printStackTrace();
	throw e;
	// throw new Exception(e);
}
...
copyWorker.setOnFailed(evt -> {
    System.out.println("Task failed!");
    if (copyWorker.getException() instanceof IndexOutOfBoundsException) {
	System.out.println("...with an IndexOutOfBoundsException");
    } else if (copyWorker.getException() instanceof NumberFormatException) {
	System.out.println("...with a NumberFormatException");
    } else {

	System.out.println("...with another, unexpected execption");

    }

    Optional<ButtonType> result = Helper.enviarPergunta(AlertType.ERROR, "Ocorreu um Erro",
	    "Houve um erro na verificação do arquivo!", 
	    "Mensagem: " + copyWorker.getException().getLocalizedMessage());

    if (result.get() == ButtonType.OK) {

	editMode.set(true);
	modeTask.set(true);
	btnVrfFile.disableProperty().bind(editMode.not());
	btnSelectFile.disableProperty().bind(editMode.not());
	progress.progressProperty().unbind();
	progress.setProgress(0);
    }

    System.out.println(copyWorker.getException().getLocalizedMessage());
    System.out.println(copyWorker.getException().getCause());
    System.out.println(copyWorker.getException().getStackTrace());

});