Consuming OData services in Android apps

I am always grateful when using open source contributed by volunteers.  The critique here is intended to make my own contribution to improve the open source projects.

Nothing sounds more suitable than odata4j when it comes to consuming OData services in Java.  With odata4j, using OData services means only a few lines of code. The problem is I cannot figure out how to construct the first and most important line of code - constructing an instance of ODataConsumer.

Restlet is surely a more mature, better documented open source project. It appears to be able to serve the purpose of consuming OData service well. Here, the problem is I cannot finish the first step - use the client proxy class generation tool to generate the java code for the targeted service.  The command "java -jar org.restlet.ext.odata ..." generates the following:

Error: Could not find or load main class org.restlet.ext.odata.Generator.

Well, OData is based on a REST-ful protocol - AtomPub, and uses Json as one of the data formats.  Both REST-fulness and Json are supposed to make life easier. This is true.  It is easy enough that one does not have to use any tools to consume the OData services.  All one needs to do is spending a few minutes learning how to build URI's for querying data, then retrieving the data with any of many options to get a web page content, and parse it using Gson or a simiar library.

A noteworthy note: WCF data services do not support $format which can be used to specify data format such as Json.  One needs to use header "Accept" (value: application/json) of a web request to get Json data.