Java Authentication is a process that verifies the identity of users or systems trying to access a Java application. It ensures that only authorized individuals can access sensitive data or perform specific actions within the application. This is typically achieved through various methods, such as username and password combinations, tokens, or biometric data. In Java, authentication can be implemented using libraries and frameworks like Java EE Security or Spring Security. These tools provide built-in mechanisms to handle user credentials securely, manage sessions, and enforce access controls, making it easier for developers to create secure applications.