Vaadin binder throw an exception on empty field

Question

In my Vaadin (v.23.2.6) application I have a form tied up to Filter class which has 5 attributes. All of them are optional, i.e. user can leave the blank.

 public FilterPanel(ApiBookUtils api) {
    this.api = api;
    this.authorField = new ComboBox<Author>("Author Name");
    this.countryField = new ComboBox<>("Country");
    this.countryField.setReadOnly(true);
    this.fromYear = new IntegerField ("From");
    this.fromYear.setWidth("60px");
    this.toYear = new IntegerField ("To");
    this.toYear.setWidth("60px");
    this.binder = new Binder(Filter.class);
    this.setModal(true);
    this.setCloseOnOutsideClick(false);
    this.setCloseOnEsc(true);
    buildDialog();
}

private void buildDialog() {
    bindFields();
    addFields();
    setDialogListeners();
    setDialogItems();
}
private void bindFields() {
    this.binder.bind(authorField, Filter::getAuthor, Filter::setAuthor);
    this.binder.forField(countryField).bind(Filter::getCountry, Filter::setCountry);
    this.binder.forField(fromYear).bind(Filter::getFromYear, Filter::setFromYear);
    this.binder.forField(toYear).bind(Filter::getToYear, Filter::setToYear);
    this.binder.forField(postingDateField).bind(Filter::getPostingDate, Filter::setPostingDate);
    this.binder.forField(tagField).bind(Filter::getTags, Filter::setTags);
}

I am getting getting exception if IntegerField is left blank.

com.vaadin.flow.data.binder.BindingException: An exception has been thrown inside binding logic for the field element [label='From'] at com.vaadin.flow.data.binder.Binder$BindingImpl.execute(Binder.java:1570) ~[flow-data-23.2.5.jar:23.2.5] at com.vaadin.flow.data.binder.Binder$BindingImpl.writeFieldValue(Binder.java:1427) ~[flow-data-23.2.5.jar:23.2.5] at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na] Caused by: java.lang.NullPointerException: null at com.vaadin.flow.data.binder.Binder$BindingImpl.lambda$writeFieldValue$5169480d$1(Binder.java:1431) ~[flow-data-23.2.5.jar:23.2.5]

Does anybody know how to make binder to accept empty field and set up default value in the bean?

Answer 1

I found the workaround the bug in the Binder. Apparently, it does not process primitive types correctly. I have replaced int fields in my bean with Integer object and exception was gone.