We have a server application (implemented in Java) that will provide some data for our mobile apps. The apps will be created for Android and iOS.
Which is the best proto
In My Opinion, you should use REST/SOAP web sevices based on document-oriented structures, This will be helpful in the Large response.
You can also integerate Apache SOLR for this Purpose this is used for Indexing the Large Datasets and is even much faster and it is also REST enabled, you can index your data in the SOLR cores and then create REST calls from Client i.e. IOS, Android, PHP etc. so the documents will already be processed and you just need to add filters and other things as required on client.
Let me know if you want any more help regarding this.