final Form form = new Form();
final FormField<String> field1 = new StringTextBoxFormField();
field1.setValidator(new NotEmptyFieldValidator());
final FormField<String> field2 = new StringTextBoxFormField();
field2.setValidator(new DoubleFieldValidator());
final FormField<String> field3 = new StringTextBoxFormField();
field3.setValidator(new CompositeFieldValidator(new NotEmptyFieldValidator(), new DoubleFieldValidator()));
final FormField<String> field4 = new StringTextBoxFormField();
field4.setValidator(new CompositeFieldValidator(new NotEmptyFieldValidator(), new EmailFieldValidator()));
final FormField<Boolean> field5 = new CheckBoxFormField();
field5.setValidator(new UncheckedFieldValidator());