Which Java API is used for creating WebSocket applications in Java EE?
- java.socket
- java.web
- javax.communication
- javax.websocket
The javax.websocket API is used for creating WebSocket applications in Java EE, providing classes and interfaces to work with the WebSocket protocol.
In the context of servlets, what is a key difference between HTTP and WebSocket protocols?
- Connectionless protocol
- Full-duplex communication
- Request-Response model
- Stateless communication
A key difference between HTTP and WebSocket protocols is that WebSocket enables full-duplex communication, allowing both the client and server to send messages independently in real-time.
How does the WebSocket protocol handle message framing compared to HTTP?
- Messages are framed using JSON format.
- Messages are framed using XML format.
- Messages are framed using headers and payload.
- Messages are not framed; they are sent as a continuous stream.
The WebSocket protocol handles message framing by using headers and payload, unlike HTTP, where messages are not framed, and they are sent as a continuous stream.
What is the role of @ServerEndpoint annotation in Java WebSocket API?
- It configures the server's endpoint settings.
- It defines the client's endpoint in a WebSocket connection.
- It handles exceptions during WebSocket communication.
- It marks a class as a WebSocket endpoint.
The @ServerEndpoint annotation in Java WebSocket API is used to mark a class as a WebSocket endpoint, allowing the class to handle WebSocket communication on the server side.
How are WebSocket connections initiated in the context of a servlet-based web application?
- They are automatically established when the web application starts.
- They are initiated through a dedicated WebSocket servlet.
- They are initiated using the openConnection() method.
- They require manual configuration in the web.xml file.
WebSocket connections in a servlet-based web application are initiated through a dedicated WebSocket servlet, which is configured to handle WebSocket communication.
What mechanism does WebSocket use to achieve full-duplex communication?
- Long Polling
- Polling
- Request-Response
- WebSocket uses its own protocol
WebSocket achieves full-duplex communication by using its own protocol, which enables bidirectional communication between the client and the server in real-time without the need for constant polling.
How can a servlet-based application detect and handle WebSocket upgrade requests?
- By inspecting the payload
- Using the Connection header
- Using the Upgrade header
- WebSockets cannot be used with servlets
A servlet-based application can detect and handle WebSocket upgrade requests by inspecting the Upgrade header in the HTTP request, indicating the intention to switch protocols to WebSocket.
Describe the lifecycle of a WebSocket in a Java web application.
- Connect, Communicate, Disconnect
- Create, Transmit, Terminate
- Handshake, Data Transfer, Termination
- Initialization, Open, Close
The lifecycle of a WebSocket in a Java web application involves a handshake phase, followed by data transfer, and finally, termination. This sequence includes establishing the connection, exchanging data, and closing the connection.
A WebSocket connection is established with a _________ handshake upgraded from an HTTP connection.
- SSL/TLS
- TCP
- UDP
- WebSocket
A WebSocket connection is established with a "WebSocket" handshake upgraded from an HTTP connection.
In Java EE, the _________ method is used to send a message to the connected WebSocket client.
- broadcastMessage()
- sendMessage()
- sendText()
- writeMessage()
In Java EE, the sendMessage() method is used to send a message to the connected WebSocket client.