What is the meaning of the term “Thread-Safe”?

The term "thread-safe" refers to a property of code that ensures it functions correctly when accessed by multiple threads simultaneously. In a multi-threaded environment, thread-safe code prevents data races and ensures that shared data structures are manipulated in a manner that guarantees safe execution by multiple threads at the same time.

Key Points of Thread Safety:

1. Correctness Under Concurrency:

   • Thread-safe code behaves correctly when accessed from multiple threads, regardless of the scheduling or interleaving of those threads by the runtime environment[1][2][3][8].

2. Avoidance of Data Races:

   • Thread safety involves avoiding data races, which occur when multiple threads access and modify shared data concurrently without proper synchronization, leading to unpredictable results[4][6][7].

3. Synchronization Mechanisms:

   • Various strategies can be employed to achieve thread safety, including:
     • Synchronization: Using locks or other synchronization primitives to control access to shared resources[3][7][8].
     • Immutability: Making shared data immutable so that it cannot be modified after creation[3][8].
     • Thread Confinement: Ensuring that data is only accessible by a single thread[3][8].
     • Thread-safe Data Types: Using data structures that are inherently thread-safe[3][8].

4. Performance Considerations:

   • While thread safety is crucial for correctness, it often comes with a performance cost due to the overhead of synchronization mechanisms. Therefore, it is sometimes preferable to use non-thread-safe alternatives in single-threaded contexts for better performance[1][4].

5. Levels of Thread Safety:

   • There are different levels of thread safety, such as:
     • Serializable: Ensuring that code can be executed by multiple threads in a serialized manner using a single lock.
     • MT-Safe: Allowing multiple threads to execut...