How to force garbage collector to run?

Interviewer asked me about this today there an answer ?

System.GC.Collect() forces garbage collector to run. This is not recommended but can be used if situations arise.

Best Practice for Forcing Garbage Collection in C#, You can force garbage collection either to all the three generations or to a specific generation using the GC. Collect() method. The GC. Collect() method is overloaded -- you can call it without any parameters or even by passing the generation number you would like to the garbage collector to collect. Is it possible to force garbage collector to run? - Yes, we can force garbage collector to run using System.GC.Collect (). - It can be used to avoid calling any of the collect methods and allow the garbage collector to run independently. - It is better at determining the best time to perform a collection.

It is not recommended to call gc explicitly, but if you call


It will call GC explicitly throughout your code, don't forget to call GC.WaitForPendingFinalizers(); after GC.Collect().

My two cents on GC.Collect method in C#, Forces garbage collection. are not collected. Use this method to force the system to try to reclaim the maximum amount of available memory. Starting with the . There might be times in your application when you want to force the .NET Garbage Collector (GC) to spin through all unused objects and de-allocate them. The method for accomplishing this task is the GC.Collect method. When you call GC.Collect, the GC will run each object's finalizer on a separate thread. Therefore, another method to keep in mind is GC.WaitForPendingFinalizers.


from MDSN,

Use this method to try to reclaim all memory that is inaccessible.

All objects, regardless of how long they have been in memory, are considered for collection; however, objects that are referenced in managed code are not collected. Use this method to force the system to try to reclaim the maximum amount of available memory.

GC.Collect Method (System), This module provides an interface to the optional garbage collector. To debug a leaking program call gc.set_debug(gc. for a number of built-in types are cleared whenever a full collection or collection of the highest generation (2) is run . Java Force Garbage Collection – Code Example Garbage collection in java can not be enforced. But still sometimes, we call the System.gc () method explicitly. System.gc () method provides just a "hint" to the JVM that garbage collection should run.


gc — Garbage Collector interface — Python 3.8.5 documentation, The garbage collection (GC )class provides a GC.Collect method, which you can use to give your application some direct control over the garbage collector. You can use LDP.EXE to do the garbage collection control. Here are the steps: 1. In Ldp.exe, when you click Browse on the Modify menu, leave the Distinguished name box empty. 2. In the Edit Entry Attribute box, type “DoGarbageCollection” (without the quotation marks), 3.


Keep in mind, though, that the Garbage Collector might not always clean up what you expect...

How to force Garbage Collection, You really can't make blanket statements about appropriate way to use all GC implementations. They vary wildly. So I'll speak to the .NET one� To handle the memory and thread creep, I found you can use the system's builtin garbage collection method to reign in these objects. I just add the following to the top of my foreach loop: [system.gc]::Collect() I wish I'd recalled that I'd used this before running the script I'm staring at now. It'll definitely be added before I have to run it

When is it a good idea to force garbage collection?, But still sometimes, we call the System.gc( ) method explicitly. System.gc() method provides just a "hint" to the JVM that garbage collection should run. It is not� Set the Operation value set to Add and click the Enter button, and then click Run. It’s possible that the garbage collection you start using the above method could stop in favor of more important tasks like AD replication in the same way as the scheduled garbage collection does.

Java Force Garbage Collection – Code Example, Collect method. When you call GC.Collect, the GC will run each object's finalizer on a separate thread. Therefore, another method to keep in� gc. set_threshold (threshold0[, threshold1[, threshold2]]) ¶. Set the garbage collection thresholds (the collection frequency). Setting threshold0 to zero disables collection. The GC classifies objects into three generations depending on how many collection sweeps they have survived.

C# Tip: Forcing Garbage Collection in .NET, When you click the Force Garbage Collection button, the program calls GC.Collect to force garbage collection. (See the online help for information on garbage collection generations. ' Collect all garbage generations.

  • This question has good info about why you shouldn't do that though:…
  • why are you telling like this
  • @Jason - Maybe the interviewer didn't want to hear the solution, rather get Andrew's knowledge and reasoning against doing it, then this question could effectively make sense.
  • @martinstoeckli It is still a terrible question. Someone with the knowledge in a stressful interview would not realise it is a trick question, or think to supply additional info. Then the question doesn't help the interviewer distinguish between someone with the knowledge or someone without it. So the question is still terrible.
  • "When do you force garbage collection?" sounds like a good interview question to me ("How": not so much). Beginner: I dunno. Intermediate: Never. Expert: When you write a test for memory leaks.
  • Why is it not recommended?
  • GC.Collect() is expensive to run. Doing it more than necessary is inadvisable. The code for when it should be called is well written. You should normally only self collect in specialized edge cases.
  • WaitForPendingFinalizers doesn't necessarily give "better performance": it simply blocks until all objects in the finalisation queue have been finalised (objects which might have been put there by your previous call to Collect). If you want a chance for those objects to be collected then you need another call to Collect after calling WaitForPendingFinalizers.
  • Since one of the few good reasons to call gc.Collect is as a last-ditch effort to free up resources that weren't properly disposed, WaitForPendingFinalizers would seem a necessary step. Not sure what the best practice would be to avoid calling gc.Collect excessively in such cases, though. BTW, I wonder if there's any technical reason that gc.Collect 'has' to promote generations? It would seem more useful to have generations stay put unless enough stuff has been allocated in one to justify advancing it.
  • Note for beginners in C# (like me): GC force call doesn't guarantee, some concrete unused object be removed from memory. (one way to do this is using of "using statement" (
  • Why is it supposed to be important to call WaitForPendingFinalizers?
  • What do you mean by that? What could it unexpectedly clean?