In a chat application using WebSockets, when a message is sent to a closed connection, what happens and how should it be handled?
- An error is thrown on the server-side.
- The WebSocket connection remains open for future messages.
- The client receives an error, and the server is notified.
- The message is silently discarded.
When a message is sent to a closed connection, the client should receive an error, and the server needs to be notified for proper handling and logging.
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 HTTP method is idempotent and used primarily for retrieving data?
- DELETE
- GET
- POST
- PUT
The GET method is idempotent and is used primarily for retrieving data from the server.
Which of the following techniques is effective for reducing response time in servlets?
- Disabling servlet caching.
- Increasing the servlet buffer size.
- Minimizing the use of session objects.
- Using asynchronous processing.
Using asynchronous processing in servlets is effective for reducing response time by allowing the server to handle other tasks while waiting for I/O operations, leading to improved overall system responsiveness.
How does connection pooling in servlets optimize database interactions?
- By caching database query results
- By establishing a new connection for each request
- By increasing the size of the database
- By reusing existing database connections
Connection pooling optimizes database interactions by reusing existing database connections, reducing the overhead of establishing a new connection for each request.
What is the impact of using lazy loading in servlets?
- Degrades performance by loading all resources upfront
- Has no impact on performance
- Improves performance by loading resources only when needed
- Reduces servlet flexibility
Lazy loading in servlets improves performance by loading resources only when needed, avoiding unnecessary resource loading upfront, which can lead to better response times.
Describe how a servlet can process AJAX requests using GET and POST methods.
- Both doGet and doPost methods
- Use a separate servlet for AJAX
- Use only doGet method
- Use only doPost method
A servlet can process AJAX requests using both the doGet and doPost methods. The choice depends on the nature of the AJAX request and the type of data being sent. Using both methods allows flexibility in handling various types of AJAX requests within the same servlet.