GetChanges REST call from java returning status 400

I'm trying to use the GetChanges REST API call in SharePoint 2013 from a standalone Java app using Apache HttpClient. The JSON body in the POST request body looks like this:

{"Web":true,"query":{"__metadata":{"type":"SP.ChangeQuery"}},"Update":true}

which matches the sample at:

http://msdn.microsoft.com/en-us/library/office/dn499819%28v=office.15%29.aspx

I'm setting the Accept and Content-type headers to:

"application/json;odata=verbose"

and also setting the X-RequestDigest header to the FormDigestValue from the contextinfo request.

But I get back a 400 response with this message:

"The parameter Web does not exist in method GetChanges."

If I omit the Web and Update properties from the request there is no error but I get an empty results array.