For the purpose of learning about the Vert.x core API, we will be using a modified version of our basic customer service application, which we discussed in Chapter 4, Adding Web Interfaces to Quarkus Services. You can find the source code for this example of the Chapter09/core/customer-service folder in this book's GitHub repository. We recommend that you import the project into your IDE.
Now, let's dive straight into the code. Since the Vert.x core API is based around the callback mechanism, in order to leverage asynchronous and non-blocking APIs, for our customer service example we have added two functions that will read and write a list of customers from the filesystem in JSON format. Where shall we write our ...
