The annotation _________ is used to configure the endpoint of a WebSocket server.
- @EndpointConfig
- @ServerEndpoint
- @WebSocketConfig
- @WebSocketEndpoint
The annotation @ServerEndpoint is used to configure the endpoint of a WebSocket server.
A servlet receives a POST request with JSON data. What are the steps to correctly parse and use this data?
- Use the doGet() method and manually parse the JSON data using a JSON library.
- Use the doGet() method and rely on the servlet container to automatically parse the JSON data.
- Use the doPost() method and manually parse the JSON data using a JSON library.
- Use the doPost() method and rely on the servlet container to automatically parse the JSON data.
When handling a POST request with JSON data, it is appropriate to use the doPost() method, and manual parsing is often necessary using a JSON library. The servlet container does not automatically parse JSON data.
The _________ interface in Java EE allows the server to react to WebSocket lifecycle events.
- Decoder
- Encoder
- Endpoint
- Session
The Endpoint interface in Java EE allows the server to react to WebSocket lifecycle events.
To handle binary data in a WebSocket, the _________ method is typically implemented.
- onBinaryMessage
- onClose
- onError
- onTextMessage
To handle binary data in a WebSocket, the onBinaryMessage method is typically implemented.
WebSocket connections are maintained even if the underlying _________ changes, like from HTTP to HTTPS.
- URI
- protocol
- security
- transport
WebSocket connections are maintained even if the underlying URI changes, like from HTTP to HTTPS.
Consider a scenario where a servlet application needs to update client-side widgets in real-time. Which technology would be more efficient: AJAX polling or WebSockets?
- AJAX polling
- Both are equally efficient.
- It depends on the specific use case requirements.
- WebSockets
WebSockets would be more efficient in real-time updates as they allow for bidirectional communication and eliminate the need for continuous polling, reducing latency and server load.
What happens if the init() method of a Servlet throws an exception?
- Servlet becomes inactive
- Servlet continues to initialize
- Servlet fails to initialize
- Servlet restarts
If the init() method of a Servlet throws an exception, the servlet fails to initialize, and the servlet container may mark the servlet as unavailable.
A high-frequency trading application needs to send and receive financial data with minimal latency. What WebSocket features make it suitable for this application?
- Caching and client-side data storage
- Long polling and server-sent events
- Multiplexing and low latency
- Request-response pattern and reliable message delivery
WebSockets, with features like multiplexing and low latency, are suitable for high-frequency trading applications, as they enable efficient, bidirectional communication with minimal delay in data transmission.
What is a common practice to reduce the load on a servlet?
- Caching
- Database Connection Pooling
- Lazy Loading
- Multithreading
Database Connection Pooling is a common practice to reduce the load on a servlet by efficiently managing and reusing database connections, improving performance.
Which of the following is a recommended approach to handle database connections in servlets?
- Closing connections after each request
- Connection pooling
- Opening new connections for each request
- Using a singleton connection
Connection pooling is a recommended approach for handling database connections in servlets, as it optimizes resource usage and enhances performance.