onAccept
Runs onAccept when this text field accepts its value - the field's own action event, the one its Enter binding fires - so a search box, a command entry or a login form acts on the keyboard.
Requires a JTextField target, which covers TextField, PasswordField and FormattedTextField whichever overload of them is used. It rides the field's own Enter binding rather than replacing it, so a formatted field commits its edit first and runs nothing at all when that edit does not parse; binding the Enter key with onKeyStroke instead takes that behavior over.
Multiple applications all fire, and onAccept is read live, so passing a fresh lambda each recomposition is fine.
Return
this chain with the accept handler declared on it.
Parameters
takes no argument: the accepted value is the one the composition already declared.