garbage-collection

问题 Will GC collect object a and b if they only have reference to each other? Can you help explain the reason or give a referece doc to explain that logic. Thanks much 回答1: Yes they will be candidate to GC if no more strong references to it exist. It's important to note that not just any strong reference will hold an object in memory. These must be references that chain from a garbage collection root . GC roots are a special class of variable that includes : Temporary variables on the stack (of

问题 I'm having some problems, don't know why, when I logout from my application which is handled by FOSUserBundle since current session is never destroyed or even clear which is causing issues when I login back cause I store some data on session. This is how my security.yml looks like: security: encoders: FOS\UserBundle\Model\UserInterface: sha512 role_hierarchy: ROLE_USER: ROLE_USER ROLE_ADMIN: ROLE_ADMIN providers: fos_userbundle: id: fos_user.user_provider.username_email firewalls: dev:

问题 My Empty infinity loop public static void main(String[] args) { while (true) {} } And profiling in Java VisualVM (picture) As you can see, I do not create objects. Why change a heap? Please explain the effect. Why? 回答1: Basically any Java application is multithreaded, the fact that your main thread does not allocate memory does not mean that the others do not allocate either. In fact it is very likely that by attaching via VisualVM and showing the GC tab you have spawned some threads in the

问题 I've encountered an issue with finalizable objects that doesn't get collected by GC if Dispose() wasn't called explicitly. I know that I should call Dispose() explicitly if an object implements IDisposable , but I always thought that it is safe to rely upon framework and when an object becomes unreferenced it can be collected. But after some experiments with windbg/sos/sosex I've found that if GC.SuppressFinalize() wasn't called for finalizable object it doesn't get collected, even if it

问题 The Java code is as follows: Random r = new Random(1234697890); HashMap<Integer, List<Integer>> map = new HashMap<Integer, List<Integer>>(); List<Integer> list = new ArrayList<Integer>(); for(int i=0;i<100000;i++){ for(int j=0;j<1000;j++){ list.add(r.nextInt(100000)); } map.put(i, list); map.remove(i); } when i reaches 37553 , java.lang.OutOfMemoryError: Java heap space happens. It seems that garbage collection does not happen in the loop. Now I wonder how to fix the problem. 回答1: Try

问题 One point is wondering in my mind since last few days. I want to know how Garbage collector work with static classes, variables? As we all know Garbage collector keep track of objects that has been created in application and removed them automatically when they are no longer in use. For static class no object is created and it loaded in the memory with the application debug. So Garbage collector handle static classes? 回答1: Static classes don't need to be removed since they are not objects and

问题 As far as I know , in java if we want to manually call the garbage collector we can do System.gc(). 1.What are the operations that we do inside our overriden finalize() method? 2.Is it required to override the finalize() method if we want to manually call the JVM garbage collector? 回答1: What are the operations that we do inside our overriden finalize() method? Free memory alocated manually (through some native calls) i.e. not managed by GC. It is a really rare situation. Some people put there

问题 (This question was first asked in the Ninject Google Group, but I see now that Stackoverflow seems to be more active.) I'm using the NamedScopeExtension to inject the same ViewModel into both the View and the Presenter. After the View have been released, memory profiling shows that the ViewModel is still retained by the Ninject cache. How can I make Ninject release the ViewModel? All ViewModels are released when the Form is Closed and Disposed, but I'm creating and deleting Controls using a

问题 I'm editing an image with PIL (Python Imaging Library). On each step (convert, rotate, resize ...) there are more images created. (An excerpt from the documentation: "Returns a copy of an image rotated the given number of degrees ...") So I want to release memory. Do you know whether the following approach saves memory? import PIL.Image image = PIL.Image.open('Image.jpg') garbage = image image = image.convert('RGB') del garbage 回答1: You don't need to make the temporary garbage reference. When

问题 Suppose I have a doubly linked list. I create it as such: MyList list = new MyList(); Then I add some nodes, use it and afterwards decide to throw away the old list like this: list = new MyList(); Since I just created a new list, the nodes inside the old memory area are still pointing to each other. Does that mean the region with the old nodes won't get garbage collected? Do I need to make each node point to null so they're GC'd? 回答1: No, you don't. The Java GC handles cyclic references just