This abridged example is a simplified version of the one described in the MSDN article found at https://msdn.microsoft.com/en-us/library/mt595797.aspx.

The pattern of registering an app to access the web API is the same when using the Web API outside of your Dynamics 365 instance. We also covered a Java client example in the Connecting to Dynamics CRM from other systems OData (Java) recipe of Chapter 5, External Integration.

Microsoft also provides many variations of the ADAL libraries for different languages and frameworks at https://github.com/AzureAD/. You will find versions for Angular.js, Python, Android, and Objective C, among others.