runtime

Runtime - why is freeMemory() not showing memory consumed correctly?

六月ゝ 毕业季﹏ 提交于 2019-12-30 05:07:08
问题 Below is the code snippet to examine the memory public class TestFreeMemory { public static void main(String ... args){ Runtime rt = Runtime.getRuntime(); System.out.println("Free Memory (Before GC): " + rt.freeMemory()); rt.gc(); System.out.println("Free Memory (After GC1): " + rt.freeMemory()); rt.gc(); // Second time to ensure results are consistent // MAY BE has collected all non-reachable objects System.out.println("Free Memory (After GC2): " + rt.freeMemory()); String s = new String(

maven详解scope

我们两清 提交于 2019-12-30 04:33:33
maven的scope相信很多人都有些迷糊 问题1:scope在哪里? 问题2:scope是什么? 问题3:scope怎么用? 我们来一一解答这些问题。 1.scope在哪里? 我们都知道,dependency里面有三个元素:g,a,v(groupID,artifactID,version) 其实dependency里面还有几个其它的元素。 其中有一个就是scope 2.scope是什么 ? scope是控制该外部包在程序的运行中的哪个时期被使用,编译,测试,运行这三个阶段中的哪一个。 scope有5个可选值:compile,test,provided,runtime,system 对应的三个阶段对应的可选值:compile,test,runtime scope的设置可以给最终打包的时候的大小控制 3.scope怎么用? compile: compile是我们使用的最多的一个(也是scope的默认的一个,如果不写scope属性,那么就是compile) complie是指的是编译,测试,运行中都会用到,也就是说,默认的是所有的环节都会用到。 test: test是测试的时候用的,也就是说不参与打包,那么也就是说打包的时候会小一些 比如说junit一般都是test,也就是说在测试环节会用到,但是正式环节不会用到,那么就可以用到test runtime:

Is it possible to generate and run TemplateHaskell generated code at runtime?

拟墨画扇 提交于 2019-12-30 03:22:12
问题 Is it possible to generate and run TemplateHaskell generated code at runtime? Using C, at runtime, I can: create the source code of a function, call out to gcc to compile it to a .so (linux) (or use llvm, etc.), load the .so and call the function. Is a similar thing possible with Template Haskell? 回答1: Yes, it's possible. The GHC API will compile Template Haskell. A proof-of-concept is available at https://github.com/JohnLato/meta-th, which, although not very sophisticated, shows one general

容器生态系统

无人久伴 提交于 2019-12-29 14:43:53
本文首发于我的公众号 Linux云计算网络(id: cloud_dev) ,专注于干货分享,号内有 10T 书籍和视频资源,后台回复 「1024」 即可领取,欢迎大家关注,二维码文末可以扫。 说起生态,不禁让人想起贾跃亭的乐视,想当初我多次被它的生态布局给震撼到,一度相信它将要超越百度,坐拥互联网三大江山的宝座,但没过时日,各种劲爆的新闻就把它推到了风口浪尖上,现在想想也是让人唏嘘,但不管怎么说,愿它好吧,毕竟这种敢想敢做的精神还是值得敬佩的。 回到技术这个领域,不得不说,技术更新迭代的速度快得让人应接不暇,就容器技术这个领域来说,从 Docker 面世短短的 2-3 年时间里,就衍生出多种与之相关的技术框架,由此形成了一个小小的生态系统。 一谈到容器,大家都会想到 Docker,本文也主要从 Docker 角度来讲容器生态系统。 容器基础技术 Docker 的本质是利用 Linux 内核的 namespace 和 cgroups 机制,构建出一个隔离的进程(容器进程)。所以,容器的基础技术主要涉及到 Linux 内核的 namespace 和 cgroups 技术。 容器核心技术 容器核心技术保证容器能够在主机上运行起来,包括容器规范、容器 runtime、容器管理工具、容器定义工具、Registry 和容器 OS。 容器规范旨在将多种容器(如 OpenVZ,rkt,Docker

How fast is D compared to C++?

徘徊边缘 提交于 2019-12-29 10:07:09
问题 I like some features of D, but would be interested if they come with a runtime penalty? To compare, I implemented a simple program that computes scalar products of many short vectors both in C++ and in D. The result is surprising: D: 18.9 s [see below for final runtime] C++: 3.8 s Is C++ really almost five times as fast or did I make a mistake in the D program? I compiled C++ with g++ -O3 (gcc-snapshot 2011-02-19) and D with dmd -O (dmd 2.052) on a moderate recent linux desktop. The results

Android how to change the application language at runtime

混江龙づ霸主 提交于 2019-12-29 03:35:08
问题 I want to let the user change the language of my application using spinner (or any way). I tried many ways but they change the language of this activity not all activities, and I want to save it so when the user restart the app he will find the last choosed language. 回答1: you can use this code in spinner or any way you want String languageToLoad = "en"; // your language Locale locale = new Locale(languageToLoad); Locale.setDefault(locale); Configuration config = new Configuration(); config

136. single-number

一笑奈何 提交于 2019-12-28 13:04:16
description: Given a non - empty array of integers , every element appears twice except for one . Find that single one . Note : Your algorithm should have a linear runtime complexity . Could you implement it without using extra memory? Example 1 : Input : [ 2 , 2 , 1 ] Output : 1 Example 2 : Input : [ 4 , 1 , 2 , 1 , 2 ] Output : 4 code: func singleNumber ( nums [ ] int ) int { nRet := 0 for _ , v := range nums { nRet ^= v } return nRet } result: personal opinion: 来源: CSDN 作者: sky527759 链接: https://blog.csdn.net/sky527759/article/details/103743027

How to calculate memory usage of a Java program?

牧云@^-^@ 提交于 2019-12-28 12:27:06
问题 If I use the Runtime class ( freeMemory() , totalMemory() , and gc() ), then it gives me memory above MB (i.e. 1,000,000 bytes). But if I run the same code on any online compiler, then they show memory used in KB (i.e. 1000 bytes). This is a huge difference. This means Runtime does not show the actual memory used by the program. I need to calculate actual memory used by the program. What is the way these online compilers use to calculate memory used by the program? 回答1: First calculate the

PHP exec() performance

一曲冷凌霜 提交于 2019-12-28 06:18:18
问题 The following PHP code does return me a runtime of about 3.5 seconds (measured multiple times and averaged): $starttime = microtime(true); exec('/usr/local/bin/convert 1.pdf -density 200 -quality 85% 1.jpg'); $endtime = microtime(true); $time_taken = $endtime-$starttime; When i run the same command over a ssh terminal, the runtime is reduced to about 0.6 seconds (measured with the command line tool time ). The version of the imagemagick library is Version: ImageMagick 6.7.0-10 2012-12-18 Q16

How do I generate XML resources at runtime on Android?

别等时光非礼了梦想. 提交于 2019-12-28 05:45:16
问题 I have different strings.xml files in my resources folders (values, values_fr, values_de...), and I would like to load additional translations during runtime. Is it possible to add the new strings to those files even if it has already been compiled? Or is there a workaround? 回答1: The simple answer is that you can't. You can't modify hard-coded stuff into APK resources. But there are some options. For instance you can: Let's say read a resource, modify it, and save it into another external