What are the risks associated with concurrent access to a variable by multiple threads?

Concurrent access to the same variable from multiple threads can lead to the following risks:

• Race conditions: when multiple threads read and write to a variable simultaneously, the final value can be unpredictable.
• Data integrity violations: due to lack of synchronization, data may end up in an inconsistent state.
• Visibility issues: changes made by one thread may not immediately become visible to others due to caching or processor optimizations.

To avoid these problems, synchronization mechanisms are used: mutexes, synchronized blocks, atomic operations, and other means that ensure correct access order.