Can anyone please tell me why the simple code below throws a null pointer exception when the user deletes all characters from the field (the field is blank)? Am I doing something wrong or a null check missing somewhere? Thanks![code]
public class CalcFocusView extends VerticalLayout implements View {
public class Data {
private double amount;
public double getAmount() {
return amount;
}
public void setAmount(double amount) {
this.amount = amount;
}
}
private Data data;
@Override
public void enter(ViewChangeEvent event) {
data = new Data();
TextField field = new TextField(“Enter amount”);
addComponent(field);
Binder binder = new Binder<>(Data.class);
binder.forField(field).withValidator(value->value != null, “Empty value”).withConverter(new StringToDoubleConverter(“Please enter an amount”)).bind(“amount”);
binder.setBean(data);
}
}
[/code]
Exception:
null
sun.reflect.GeneratedMethodAccessor118.invoke(Unknown Source) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:498) com.vaadin.data.BeanPropertySet.invokeWrapExceptions(BeanPropertySet.java:367) com.vaadin.data.BeanPropertySet.access$200(BeanPropertySet.java:48) com.vaadin.data.BeanPropertySet$BeanPropertyDefinition.lambda$getSetter$2658adf8$1(BeanPropertySet.java:187) com.vaadin.data.Binder$BindingImpl.lambda$writeFieldValue$22abd369$1(Binder.java:951) com.vaadin.data.SimpleResult.handle(SimpleResult.java:78) com.vaadin.data.Result.ifOk(Result.java:146) com.vaadin.data.Binder$BindingImpl.writeFieldValue(Binder.java:951) com.vaadin.data.Binder$BindingImpl.handleFieldValueChange(Binder.java:918) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:498) com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510) com.vaadin.event.EventRouter.fireEvent(EventRouter.java:211) com.vaadin.event.EventRouter.fireEvent(EventRouter.java:174) com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1030) com.vaadin.ui.AbstractField.setValue(AbstractField.java:144) com.vaadin.ui.AbstractTextField$AbstractTextFieldServerRpcImpl.setText(AbstractTextField.java:58) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
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