What do you use more often: locks or higher isolation levels?

In Java development practice, locks (mutexes) are more commonly used to manage concurrent access to resources than increasing the transaction isolation level. Locks allow for more flexible and precise control of thread synchronization, minimizing blocking and improving performance.

Increasing the transaction isolation level (for example, to SERIALIZABLE) often leads to reduced performance due to increased locking at the database level and potential deadlocks. Therefore, this approach is used only when strict data consistency is necessary.

An example of using ReentrantLock in Java:

import java.util.concurrent.locks.ReentrantLock;

public class Counter {
    private int count = 0;
    private final ReentrantLock lock = new ReentrantLock();

    public void increment() {
        lock.lock();
        try {
            count++;
        } finally {
            lock.unlock();
        }
    }

    public int getCount() {
        return count;
    }
}