The __________ area in JVM memory is used to store per-class structures.
- Class
- Heap
- Method
- Stack
The Class area in JVM memory is used to store per-class structures, such as class metadata, constants, and static fields.
A Java application experiences 'OutOfMemoryError'. What could be the potential causes and solutions?
- Implement caching mechanisms
- Increase heap size using -Xmx
- Optimize code for memory leaks
- Reduce the number of threads
'OutOfMemoryError' may occur due to memory leaks. Optimizing code, reducing threads, and implementing caching mechanisms are strategies to address this issue. Increasing heap size is a solution but doesn't address the root cause of the problem.
When optimizing memory usage in a Java application, what strategies should be considered?
- Disable JIT compilation
- Disable garbage collection
- Increase object creation
- Use data structures efficiently
Efficient use of data structures is crucial for memory optimization. Disabling garbage collection, increasing object creation, and disabling JIT compilation are not recommended strategies and can negatively impact memory usage.
When implementing a servlet to handle form data from a dynamically generated form with varying field names, what strategy should be employed?
- Ignore dynamic form fields for security
- Iterate through request parameters
- Use fixed field names for all form elements
- Use hidden fields to store dynamic names
The recommended strategy is to iterate through request parameters, allowing dynamic handling of varying field names in a dynamically generated form. This approach ensures that all form data, regardless of field names, can be processed dynamically.
In a high-performance Java application, how should memory management be approached to prevent latency issues?
- Frequent use of finalize method
- Implement lazy loading for classes
- Opt for a large heap size
- Utilize efficient garbage collectors
Utilizing efficient garbage collectors is essential for high-performance applications. Implementing lazy loading, opting for a large heap size, and frequent use of the finalize method can lead to latency issues and should be avoided in performance-sensitive applications.
What is the primary purpose of caching in web applications?
- To add security
- To design the user interface
- To handle user authentication
- To improve performance
The primary purpose of caching in web applications is to improve performance by storing frequently accessed data and reducing the need to fetch it from the original source repeatedly.
In the context of web applications, what does 'cache invalidation' refer to?
- Clearing the browser cache
- Encrypting cached data
- Refreshing cached data
- Storing data in cache
'Cache invalidation' in the context of web applications refers to the process of refreshing or clearing cached data to ensure that users receive the most up-to-date information from the server.
What is the main difference between 'write-through' and 'write-back' caching strategies?
- Write-through and write-back are terms used interchangeably.
- Write-through and write-back caching strategies are essentially the same.
- Write-through involves writing data to both the cache and the underlying storage immediately, while write-back involves writing to the cache first and updating the underlying storage at a later time.
- Write-through involves writing data to the cache only, while write-back involves writing data to both the cache and the underlying storage simultaneously.
The main difference is that 'write-through' immediately updates both the cache and the underlying storage, while 'write-back' involves updating the cache first and delaying the update to the underlying storage.
In distributed systems, what is a cache stampede and how is it typically mitigated?
- A cache stampede is a networking issue that results in delayed cache updates.
- A cache stampede is a planned event in which caches are forcibly cleared and refreshed simultaneously.
- A cache stampede is an outdated concept and is no longer relevant in modern distributed systems.
- A cache stampede is when multiple processes or nodes simultaneously attempt to load the same cache entry that is currently not in the cache.
A cache stampede occurs when multiple processes try to load the same cache entry simultaneously. It is typically mitigated by using cache locks, semaphore mechanisms, or by allowing only one process to regenerate the cache entry.
How does 'cache eviction' differ from 'cache invalidation' in caching strategies?
- Remove all items
- Remove least frequently used items
- Remove least recently used items
- Remove outdated items
In caching strategies, 'cache eviction' involves removing the least recently used or least frequently used items, while 'cache invalidation' is about removing outdated items.