The tutorial explores the comprehensive process of designing and implementing a RESTful API using Java, specifically with Spring Boot and Jersey. It highlights key concepts of RESTful architecture, such as the use of resources, statelessness, and HTTP methods, while emphasizing best practices like resource hierarchies and API versioning. A hypothetical image catalog system is used to illustrate these principles, with a focus on creating a robust API that allows external clients to interact with the system. The implementation phase involves setting up JSON schemas, using JAX-RS annotations, and generating POJOs with the Jackson library. The tutorial also covers documenting the API with Swagger for interactive exploration and error handling using JAX-RS exceptions. Finally, the API is deployed to a server and published on RapidAPI, showcasing the importance of making APIs discoverable and usable by external developers.