What method does Liferay use to integrate with external REST services?

Liferay utilizes the JSON web service interface to integrate with external REST services, which is aligned with modern web development practices. The JSON format is lightweight and easy to parse, making it particularly suitable for communication between a client and a server over RESTful APIs. This choice offers several advantages, such as compatibility with JavaScript and many other programming languages, which facilitates seamless data exchange and interaction with external applications.

Unlike SOAP-based interfaces, which are more rigid and typically rely on XML, the JSON web service interface allows for a more flexible approach to accessing resources. This flexibility enables developers to utilize Liferay in diverse environments while easily integrating with various RESTful services, enhancing Liferay's extensibility and integration capabilities.

The other methods mentioned, such as SOAP and XML-RPC, represent older paradigms for web services that are not as commonly used in conjunction with RESTful services today. GraphQL is also a more recent technology, but it is distinct from REST. Therefore, the JSON web service interface is the most appropriate and widely used method for Liferay's integration with external REST services.