Which of the following is a recommended method for adding third-party JavaScript libraries?

Using hosted libraries with the define function is a recommended method for adding third-party JavaScript libraries in Liferay. This approach leverages the AMD (Asynchronous Module Definition) pattern, which allows for better modularization and loading management of JavaScript dependencies. By using the define function, developers can ensure that scripts are loaded only when needed and that dependencies are managed correctly, promoting efficient loading and reducing the risk of conflicts between libraries.

In Liferay, adopting this method aligns well with the platform's best practices, encouraging modular development and easy integration of third-party scripts. This can lead to improved performance and maintainability of custom themes and applications within the Liferay ecosystem.

Other methods, while potentially functional, do not adhere to best practices in JavaScript development or Liferay’s framework. For instance, using only inline scripts can lead to difficulties in debugging and reduce separation of concerns within the codebase. Adding script tags without Liferay's loading mechanism could result in performance issues or conflicts with Liferay’s own JavaScript libraries. Likewise, embedding scripts directly into HTML documents can create maintainability challenges and prevent efficient caching by the browser. Hence, using hosted libraries with the define function stands out as the most effective and recommended practice.