JSOHelper.eval return values

[bootz15]

I am trying to learn how to get data returned from JSOHelper.eval(). I have the following code:

JavaScriptObject jso = JSOHelper.eval("( window.location.href.indexOf('locale=') > -1)");

But I get a JavaScript error window saying:
Unexpected error has occurred.Something other than a Java object was returned from JSNI method '@com.smartgwt.client.util.JSOHelper::eval(Ljava/lang/String;)': JS value of type boolean, expected java.lang.Object

I know it's a boolean.... how do I get it back into my smartgwt code to use?

[smartgwt.dev]

You should be using Window.Location.getHref() for this.

[bootz15]

You should be using Window.Location.getHref() for this.

Thanks for the good suggestion. Just to clarify, I found that this should be the google.gwt Window class:
com.google.gwt.user.client.Window
not:
com.smartgwt.client.widgets.Window

However I'm still not sure how to return a value from JSOHelper.eval()... very hard to find documentation on this topic.

[Isomorphic]

If you're looking for the general ability to have JavaScript code in your app, that's a core function of GwT, Google "GWT JSNI".