If a servlet manipulates a shared data structure, what must be done to ensure it operates correctly in a multithreaded environment?
- Avoid multithreading in servlets.
- Synchronize access to the shared data structure.
- Use multiple instances of the servlet.
- Use volatile keyword for the shared data structure.
Synchronizing access to the shared data structure is crucial in a multithreaded environment to prevent data corruption and ensure consistency. The synchronized keyword ensures that only one thread can access the shared data structure at a time.
To handle a POST request, the HttpServlet class uses the _________ method.
- doGet()
- doPost()
- handlePost()
- servicePost()
To handle a POST request, the HttpServlet class uses the doPost() method.
Describe a scenario where it's more efficient to use local variables instead of instance variables in a servlet.
- When the variable is used within a single servlet method.
- When the variable needs to be accessed from different sessions.
- When the variable needs to retain state across multiple requests.
- When the variable should be shared among different servlet instances.
Local variables are more efficient when the variable's scope is limited to a single method and doesn't need to retain state between requests. This reduces the memory footprint and avoids unnecessary storage of data that doesn't persist beyond the method execution.
What is the primary purpose of load balancing in web applications?
- Distribute incoming traffic
- Enhance security
- Execute database queries
- Store session data
The primary purpose of load balancing in web applications is to distribute incoming traffic across multiple servers, ensuring better performance and preventing overload on a single server.
How can an HTTP servlet differentiate between GET and POST requests?
- Checking the request type in the doGet and doPost methods.
- The HTTP servlet cannot differentiate between GET and POST requests.
- Using the HttpServletRequest method getMethod()
- Using the requestType attribute in the web.xml file.
An HTTP servlet can differentiate between GET and POST requests by using the HttpServletRequest method getMethod(), which returns the HTTP method of the request (e.g., "GET" or "POST"). This allows the servlet to determine the type of request being made.
What is the basic difference between horizontal scaling and vertical scaling?
- Distributing traffic
- Increasing resources on a server
- Increasing servers
- Load balancing
The basic difference is that horizontal scaling increases the number of servers to handle increased load, while vertical scaling involves increasing the resources (CPU, RAM) on a single server.
Which load balancing algorithm distributes requests based on the server with the least connections?
- Least Connections
- Random
- Round Robin
- Weighted Round Robin
The load balancing algorithm that distributes requests based on the server with the least connections is known as the Least Connections algorithm.
In the context of web applications, what does the term 'sticky session' mean?
- A session that retains client affinity
- A session with a fixed duration
- A session with persistent data
- A session with secure connections
'Sticky session' refers to a session that retains client affinity, meaning requests from the same client are directed to the same server, enhancing user experience in stateful applications.
What is a common challenge when scaling stateful applications?
- Caching
- Data consistency
- Load balancing
- Stateless communication
Achieving Data consistency is a common challenge when scaling stateful applications, as it involves ensuring that data is synchronized across multiple instances of the application.
How does a distributed cache enhance the scalability of a web application?
- Decreases Cache Hit Rate
- Improves Session Management
- Increases Network Latency
- Reduces Database Load
A distributed cache reduces the load on the database by storing frequently accessed data, reducing the need to query the database, and thereby enhancing the scalability of a web application.