Two ways to use Gson for JSON in Java are the tree model and data binding. The tree model allows you to read JSON into a tree model: Java objects that represent JSON objects, arrays, and values, providing implicit and explicit type coercions, but resulting in verbose code and potential mixing of Gson's API with application logic. In contrast, data binding involves parsing JSON directly into objects of your design, offering straightforward JSON-to-object conversion, independent objects from Gson, and customizable mapping using Type Adapters, but requiring upfront work to create classes matching the JSON structure. Both approaches have their pros and cons, and data binding is generally recommended for more complex queries or when JSON parsing is part of a larger application, with tools like JsonSchema2Pojo assisting in class generation.