What is thread safety?
💡 Concept: Thread Safety
Thread safety means writing code that functions correctly when accessed by multiple threads concurrently without causing data corruption or unexpected behavior.
📘 Quick Intro
Thread-safe code ensures consistency and avoids race conditions in multithreaded environments.
🧠 Analogy
Imagine multiple people updating the same document simultaneously — thread safety is like having a strict edit protocol that prevents conflicting changes.
🔧 Technical Explanation
- 🔄 Synchronization mechanisms like locks, mutexes, and semaphores are used to enforce thread safety.
- ⚙️ Immutable objects and thread-local storage help avoid shared state issues.
- 🛠️ Proper use of volatile keyword ensures variable visibility across threads.
- 📚 The .NET Framework provides thread-safe collections and utilities.
- ⚠️ Failing to ensure thread safety can lead to race conditions and data corruption.
🎯 Use Cases
- ✅ Writing concurrent data structures.
- ✅ Handling shared resources in multithreaded applications.
- ✅ Implementing thread-safe singletons.
- ✅ Avoiding deadlocks and race conditions.
💻 Code Example
private readonly object _lock = new object();
private int _counter = 0;
public void Increment() {
lock (_lock) {
_counter++;
}
}
❓ Interview Q&A
Q1: What is thread safety?
A: Code correctness under concurrent access.
Q2: Name synchronization mechanisms.
A: Locks, mutexes, semaphores.
Q3: How does lock keyword help?
A: Ensures only one thread accesses critical section.
Q4: What are race conditions?
A: Unexpected behavior due to unsynchronized access.
Q5: What is immutable object?
A: Object state cannot change after creation.
Q6: Why use thread-safe collections?
A: To avoid concurrency bugs.
Q7: Can thread safety impact performance?
A: Yes, due to locking overhead.
Q8: What is volatile keyword?
A: Ensures variable visibility across threads.
Q9: How to avoid deadlocks?
A: Careful lock ordering and timeouts.
Q10: What is thread-local storage?
A: Data unique to each thread.
📝 MCQs
Q1. What is thread safety?
- Random code
- Correct code under concurrency
- Slow code
- Unsafe code
Q2. Name synchronization mechanisms?
- Variables
- Locks, mutexes, semaphores
- Methods
- Threads
Q3. How does lock help?
- Multiple access
- Single thread access
- No access
- Partial access
Q4. What are race conditions?
- Good practice
- Unsynchronized access issues
- Slow access
- No issues
Q5. What is immutable object?
- Mutable object
- Unchangeable state
- Fast object
- Dynamic object
Q6. Why use thread-safe collections?
- For speed
- Avoid concurrency bugs
- For memory
- For simplicity
Q7. Can thread safety impact performance?
- No
- Yes
- Maybe
- Sometimes
Q8. What is volatile keyword?
- Thread lock
- Variable visibility
- Method call
- No effect
Q9. How to avoid deadlocks?
- Ignore locks
- Lock ordering
- More threads
- No locks
Q10. What is thread-local storage?
- Global data
- Thread-specific data
- Random data
- Static data
💡 Bonus Insight
Thread safety is essential for reliable, bug-free multithreaded C# applications.
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