I require the services of a Java developer to build 4-5 REST APIs for my mobile app. These APIs should handle user authentication and authorization, as well as perform CRUD operations on a database. The mobile app itself is developed in Java, and it is crucial that the APIs have a quick response time of less than 1 second. The ideal candidate for this job should possess the following skills and experience:

• Proficiency in Java programming language

• Previous experience in developing REST APIs

• Understanding of user authentication and authorization mechanisms

• Familiarity with performing CRUD operations on databases

• Ability to integrate with third-party services

• Experience in optimizing API response time to ensure fast performance.