Getting 'undefined' as a value in java from Cookie?

Question

We are working with java-gwt application. We are using cookies along with all the modules in the application. In some cases i need to get the value from cookie before setting cookie.

String demoId = Cookie.get("demoId");

In the above code i am getting 'undefined' as demoId. How to handle this in java, because the 'undefined' is specific to javascript.

Answer 1

From GWT/Java point of view, JavaScript's null and undefined are the same: they're Java null . Of course they behave differently when running your app (such as when "stringifying" them) but in 99.999% of the cases they just behave the same (note that in JS (null == undefined) === true ).

So just use an == null in Java and it'll work the same whether the value actually is a JS null or undefined .