What are the performance differences between ConcurrentHashMap and SynchronizedMap?

What are the performance differences between ConcurrentHashMap and SynchronizedMap?

ConcurrentHashMap is designed for concurrent access, allowing multiple threads to read and write without locking the entire map, which improves performance. In contrast, SynchronizedMap locks the entire map for each operation, leading to potential bottlenecks in multi-threaded environments.

Can you explain how ConcurrentHashMap achieves better concurrency?

ConcurrentHashMap uses a technique called segmentation, where the map is divided into segments. Each segment can be locked independently, allowing multiple threads to operate on different segments simultaneously, thus enhancing throughput.

Are there any scenarios where SynchronizedMap might be preferable?

Yes, SynchronizedMap might be preferable in scenarios with low contention or when the map is mostly accessed by a single thread, as its simpler locking mechanism can be easier to manage.

What about memory consumption between the two?

ConcurrentHashMap generally consumes more memory due to its internal structure and segmentation, while SynchronizedMap has a lower memory footprint but may lead to higher latency under concurrent access.