finalize

how to destroy an object in java?

人走茶凉 提交于 2019-11-27 10:07:30
问题 I encountered this question in an interview with following options: How to destroy an object in java? a. System.gc(); b. Runtime.getRuntime.gc(); c. object.delete(); d. object.finalize(); e. Java performs gc by itself, no need to do it manually. The answer should be e? what if e was not there? then ? clearly c is not the answer. a and b will do gc for the whole application(question requires for one object). I think it is d because finalize() is called just prior to gc(but is it necessary that

浅谈c#和lua的gc

左心房为你撑大大i 提交于 2019-11-27 09:51:02
前提: 本文参考和借鉴相关博客,相关版权归其所有,我只是做一个归纳整理,所以本文没有任何版权 参考文献和书籍: CLR和.Net对象生存周期: https://www.cnblogs.com/Wddpct/p/5547765.html c#Finalize 和Dispose的区别: https://www.cnblogs.com/Jessy/articles/2552839.html 《Lua设计与实现》——codedump 著 一、概要 本次对常见使用的c#和lua语言的gc操作原理和过程进行一次归类整理,加深对语言的理解,也为后续写出更优性能更好的代码做相关知识储备。 二、c#的垃圾回收 2.1 基本概念 1. CLR CLR: Common Language Runtime, 公共语言运行时,是一种可以支持多种语言的运行时,其基本的核心功能包含: 内存管理 程序集加载和卸载 类型安全 异常处理 线程同步 2. 托管模块 CLR并不关心是使用何种语言进行编程开发,只要编译器是面向CLR而进行编译的即可,这个中间的结果,就是IL(Intermediate Language), 最终面向CLR编译得到的结果是:IL语句以及托管数据(元数据)组成的托管模块 PS: 元数据: 元数据的本质就是一种描述数据的数据 借鉴相关文章的图,其基本的过程为 : 托管模块的基本组成: PE32

GC垃圾回收

て烟熏妆下的殇ゞ 提交于 2019-11-27 09:23:19
GC垃圾回收器 全名: Garbage Collector 原理: 以应用程序的根(root)为基础,遍历应用程序堆(heap)上动态分配的所有对象,通过识别它们是否被引用来确定哪些对象是已经死亡的,哪些仍需要被使用,已经不再被应用程序的根(root)或者别的对象所引用的对象就是已经死亡的对象,即所谓的垃圾,需要被回收。 Mark Compact(标记压缩算法) 原理: 先假设Heap中的所有对象都可以回收,然后找出不能回收的对象,给这些对象打上标记,最后Heap中没有打标记的对象都是可以被回收的。 对象回收之后,Heap内的存储空间变得不连续,在Heap中移动这些对象,使他们重新从Heap的基地址开始连续排列。 步骤: 将线程挂起 -> 确定Roots -> 创建Reachable Object Graph(可达的对象图) -> 对象回收 -> Heap压缩 -> 指针修复 Roots: Heap中对象的引用关系错综复杂(交叉引用,循环引用),形成复杂的Graph(图),Roots是CLR在Heap之外可以找到的各种入口点。 Reachable Objects: 指根据对象引用关系,从Roots出发可以到达的对象。例如当前执行函数的局部变量对象A是一个Root object,他的成员变量引用了对象B,则B是一个Reachable object

Dispose() for cleaning up managed resources?

最后都变了- 提交于 2019-11-27 04:20:02
问题 In this answer I found, Cleanup the unmanaged resources in the Finalize method and the managed ones in the Dispose method, when the Dispose/Finalize pattern has been used in your code. And later I found this nice article about finalize and dispose and got a clear idea about them. The article has the following code( Page 3 ), to explain the concepts: class Test : IDisposable { private bool isDisposed = false; ~Test() { Dispose(false); } protected void Dispose(bool disposing) { if (disposing) {

How to ensure finalize() is always called (Thinking in Java exercise)

久未见 提交于 2019-11-27 03:21:19
问题 I'm slowly working through Bruce Eckel's Thinking in Java 4th edition , and the following problem has me stumped: Create a class with a finalize( ) method that prints a message. In main( ), create an object of your class. Modify the previous exercise so that your finalize( ) will always be called. This is what I have coded: public class Horse { boolean inStable; Horse(boolean in){ inStable = in; } public void finalize(){ if (!inStable) System.out.print("Error: A horse is out of its stable!");

Difference between destructor, dispose and finalize method

守給你的承諾、 提交于 2019-11-27 02:52:18
I am studying how garbage collector works in c#. I am confused over the use of Destructor , Dispose and Finalize methods. As per my research and understandings, having a Destructor method within my class will tell the garbage collector to perform the garbage collection in the way mentioned in the destructor method which cannot be called explicitly on the instances of the class. The Dispose method is meant to provide the user to control the garbage collection. The Finalize method frees the resources used by the class, but not the object itself. I am not sure if I understand it the right way.

In C# what is the difference between a destructor and a Finalize method in a class?

寵の児 提交于 2019-11-27 02:50:15
What is the difference, if there is one, between a destructor and a Finalize method in a class? I recently discovered that Visual Studio 2008 considers a destructor synonymous with a Finalize method, meaning that Visual Studio won't let you simultaneously define both methods in a class. For example, the following code fragment: class TestFinalize { ~TestFinalize() { Finalize(); } public bool Finalize() { return true; } } Gives the following error on the call to Finalize in the destructor: The call is ambiguous between the following methods or properties: 'TestFinalize.~TestFinalize()' and

【.NET中IDisposable接口的基本使用 】

╄→尐↘猪︶ㄣ 提交于 2019-11-26 22:28:53
http://www.cnblogs.com/carysun/articles/1222290.html 转载博客园 首先来看MSDN中关于这个接口的说明: [ComVisible( true )] public interface IDisposable { // Methods void Dispose(); } 1.[ComVisible( true )]:指示该托管类型对 COM 是可见的. 2.此接口的主要用途是释放非托管资源。当不再使用托管对象时,垃圾回收器会自动释放分配给该对象的内存。但无法预测进行垃圾回收的时间。另外,垃圾回收器对窗口句柄或打开的文件和流等非托管资源一无所知。将此接口的Dispose方法与垃圾回收器一起使用来显式释放非托管资源。当不再需要对象时,对象的使用者可以调用此方法。 一:基本应用 1.我们来定义一个实现了IDisposable接口的类,代码如下: public class CaryClass :IDisposable { public void DoSomething() { Console.WriteLine(" Do some thing.... "); } public void Dispose() { Console.WriteLine(" 及时释放资源 "); } } 2.我们有两种方式来调用: 2.1.第一种方式

Why is the retained heap size of the FinalizerReference class so large in the (memory) Profiler of Android Studio?

耗尽温柔 提交于 2019-11-26 18:39:00
问题 I have read this question about Finalizer's lion share of the heap. It dates from 2011 when the tools were different and the Java class still had a different name (Finalizer vs FinalizerReference). So I think this similar but new question can be asked now. On top of that, the accepted answer to that question boils down to: avoid using finalize()'d objects. Android classes that use finalize() directly or indirectly include Canvas, Paint, Bitmap, Drawable and RenderNode. Good luck avoiding all

Java and manually executing finalize

北战南征 提交于 2019-11-26 16:43:14
问题 If I call finalize() on an object from my program code, will the JVM still run the method again when the garbage collector processes this object? This would be an approximate example: MyObject m = new MyObject(); m.finalize(); m = null; System.gc() Would the explicit call to finalize() make the JVM 's garbage collector not to run the finalize() method on object m ? 回答1: According to this simple test program, the JVM will still make its call to finalize() even if you explicitly called it: