Creating a Websocket Server With the Java API for Websockets

This WebSocket server can handle both text and binary messages, allowing for bi-directional and real-time communication between the client and server. The Java API for WebSockets (JSR 356) provides a specification that enables developers to integrate WebSockets into their applications without being tied to a specific container's implementation. The server uses Gretty as an embedded servlet container, which can be configured to use Tomcat as the underlying container. The WebSocket endpoint is created using the `@ServerEndpoint` annotation and handles incoming messages with the `@OnMessage` annotation, allowing for echo-like behavior. A client application written in HTML and JavaScript is also provided to test the server's functionality.