What are thread races and why can they lead to errors in a multithreaded application?

Race conditions occur when multiple threads access a shared resource (such as a variable or object) simultaneously, and at least one of them modifies this resource.

The problem is that read and write operations are not atomic, and without synchronization, the result can be unpredictable. This leads to errors such as:

• Incorrect or outdated data.
• Violation of program logic.
• Crashes and failures of the application.

Example: two threads simultaneously increment a counter. If both read the value 5, increase it to 6, and write it back, the final result will be 6 instead of 7.

To avoid race conditions, synchronization mechanisms are used: locks (mutex, lock), atomic operations, volatile variables, and other means that ensure sequential access to shared data.