I did a quick Google Search and couldn't find a Google API for the cinema listings, although you could see if they expose these in the Google Base API.
One alternative would be using the Yahoo Query Language API. They do have a showtimes API that you can query in Java. Here is the YQL syntax you'd use:
select * from movies.showtimes
To get a list of all movies. Then:
select * from movies.showtimes where location='myzip' and name='one of the movies'
You could also do
select * from movies.showtimes where location='myzip' and name in whatever
You can use the console to discover what this API has to offer here: http://developer.yahoo.com/yql/console/?env=http://datatables.org/alltables.env#h=desc%20movies.showtimes
As far as implementation, I'm not a Java dev (mainly LAMP and .NET) so I can't give you code samples, but the YQL API is a RESTful API, therefore you just have to hit the API with the correct parameters in the request and it will return the XML results.
Hopefully this will help you find what you're looking for!