What is garbage collection in C#?
💡 Concept: Garbage Collection
Garbage collection (GC) in C# is an automatic memory management system that frees unused objects to optimize application performance.
📘 Quick Intro
GC monitors allocated memory and removes objects no longer referenced by the program to prevent memory leaks.
🧠 Analogy
Think of GC as a janitor who cleans up unused items in a house to keep it tidy and functional.
🔧 Technical Explanation
- 🧹 GC tracks object references to determine which objects are no longer in use.
- ♻️ Uses generations (0, 1, 2) to optimize collection frequency.
- 🕒 Runs periodically or on-demand to reclaim memory.
- 🔒 Helps prevent memory leaks and improves app stability.
- ⚙️ Developers can trigger GC manually but generally rely on automatic collection.
🎯 Use Cases
- ✅ Managing dynamic memory allocation efficiently.
- ✅ Preventing memory leaks in long-running applications.
- ✅ Improving overall application performance and responsiveness.
- ✅ Supporting managed languages like C# with automatic memory safety.
💻 Code Example
// Example of forcing garbage collection (not recommended in general)
GC.Collect();
GC.WaitForPendingFinalizers();
❓ Interview Q&A
Q1: What is garbage collection?
A: Automatic memory management that frees unused objects.
Q2: How does GC know which objects to collect?
A: It tracks object references.
Q3: What are generations in GC?
A: Groups of objects categorized by lifespan to optimize collection.
Q4: Can you manually trigger garbage collection?
A: Yes, but it's generally discouraged.
Q5: What problems does GC solve?
A: Memory leaks and fragmentation.
Q6: Is GC present in unmanaged languages?
A: No, it's specific to managed runtimes like .NET.
Q7: What is finalization?
A: Cleanup of resources before object memory is reclaimed.
Q8: What happens if GC doesn't run?
A: Memory leaks and app crashes.
Q9: How does GC affect performance?
A: It can cause pauses but overall improves memory management.
Q10: Can GC be disabled?
A: No, but it can be tuned.
📝 MCQs
Q1. What is garbage collection?
- Manual memory freeing
- Automatic memory management
- Compilation process
- Error handling
Q2. How does GC know what to collect?
- Randomly
- Tracks references
- User input
- Garbage codes
Q3. What are generations in GC?
- Memory blocks
- Object lifespan groups
- CPU cores
- Threads
Q4. Can you manually trigger GC?
- No
- Yes, but discouraged
- Always
- Never
Q5. What problem does GC solve?
- CPU load
- Memory leaks
- Slow code
- Disk fragmentation
Q6. Is GC in unmanaged languages?
- Yes
- No
- Sometimes
- Unknown
Q7. What is finalization?
- Garbage deletion
- Cleanup before reclaim
- Memory allocation
- Error fixing
Q8. What if GC doesn't run?
- Nothing
- Memory leaks and crashes
- Better performance
- Faster CPU
Q9. How does GC affect performance?
- No impact
- Can cause pauses
- Always slow
- Never slow
Q10. Can GC be disabled?
- Yes
- No
- Sometimes
- Maybe
💡 Bonus Insight
Garbage collection is vital in managed languages like C# to simplify memory management and enhance application reliability.
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