Memory & GC · interview question

Which statements about the .NET garbage collector are true? Select all that apply.

Select all that applyMedium

It's generational, with Gen 0, Gen 1 and Gen 2.Objects of 85,000 bytes or more are allocated on the Large Object Heap.Calling `GC.Collect()` regularly usually improves performance.Finalizers run deterministically as soon as an object goes out of scope.The GC can compact the heap, moving objects in memory.

Answer and explanation

Correct answer

A. It's generational, with Gen 0, Gen 1 and Gen 2.
B. Objects of 85,000 bytes or more are allocated on the Large Object Heap.
E. The GC can compact the heap, moving objects in memory.

Why

Most objects die young, so the GC collects Gen 0 often and cheaply. Survivors are promoted and the heap is compacted (the LOH isn't compacted by default). Use IDisposable for deterministic cleanup.

References

Microsoft Learn: Fundamentals of garbage collection

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