How does synchronized impact performance or memory usage?

Synchronized in Java is a mechanism that ensures that only one thread can access a particular section of code at a time. While this promotes thread safety, it can also have significant impacts on performance and memory usage.

When multiple threads attempt to access synchronized blocks, those threads are forced to wait, which can lead to thread contention. This contention can slow down an application, especially if the synchronized block takes a considerable amount of time to execute.

Additionally, synchronized methods or blocks can also lead to increased memory usage due to the inherent overhead of object locks. Each lock held by a thread can consume memory; therefore, in scenarios with excessive locking or long-held locks, overall memory consumption can increase.

To mitigate performance issues, consider limiting the scope of synchronized blocks, using more granular locking mechanisms, or even employing concurrent data structures provided by the Java concurrency framework.