As we have already seen in previous recipes, accessing OData is relatively straightforward. The power of RESTful services is in their simplicity. We issue a request with a specifically formatted URL, along with some headers, to get a JSON response. In Querying Dynamics 365 Data using the Web API endpoint, recipe of Chapter 2, Client-Side Extensions, we used JavaScript to generate our GET request. However, even though Java applications follow the same mechanism, we will need to deal with authentication as we don't have an existing session to leverage.

In this recipe we will write a Java console application to connect to Dynamics 365 online and retrieve the top three accounts ordered by name. The focus of this recipe will be on how to prepare your Azure tenancy to accept calls from a Java application and how to authenticate to receive your token that will be used to issue the correct HTTP GET request to Dynamics 365.