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  What and what not to log while debugging

Log is a critical part of an application. It serves as an eye to the programmer on how the application is working while debugging. Especially for applications running on production environment, if the application encounters problem and the problem cannot be reproduced on other environments, log will be extremely useful. While log is essential, but developers have to log smartly. Because if don't put log smartly, you may not get what you want while debugging or you may get too many...

   PROGRAMMING,DEBUG,LOG,SUPPORT     2016-03-14 08:09:03

  Browse OpenJDK Java source code in Eclipse

Java 8 was recently released, many developers are now trying to extract the source code of Java 8 to find out how the new added features such as Lambda expressions, default method in interfaces, new Time API are implemented. How do you manage to download and browse the source code? Today we are going to show how to extract OpenJDK Java source code to Eclipse. Since OpenJDK is adopting Mercurial as its distributed version control system, you need to install Mercurial on your computer first before...

   OpenJDK,Java 8,Source code,Eclipse     2014-06-16 00:53:34

  How NOT to teach a computer language

For the past year or so my wife has been taking online classes to get a computer science degree. For most of her classes she’s done great, she’s been flying through HTML and SQL, even up to the point where she can handle multilevel joins and optimizing through indexes. That was until she hit her vb.net class. I had no idea why she was having problems with a language has easy as vb.net so I started helping her out and find out why she was having so many problems. I’ve also ad...

   Programming,Teach,Book,Grade,Method,Computer     2011-11-06 14:52:13

  Cache Reheating - Not to be Ignored

An important aspect to keep in mind with databases is the cost of cache reheating after a server restart. Consider the following diagram which shows several cache servers (e.g., memcached) in front of a database server.This sort of setup is common and can work quite well when appropriate; it removes read load from the database and allows more RAM to be utilized for scaling (when the database doesn’t scale horizontally). But what happens if all the cache servers restart at the same time, s...

   Database,Cost,Cache reheating,Advice     2011-09-21 09:47:29

  Stub Mixlib::ShellOut and shell_out in Ruby unit testing

Unit testing is part of software development to ensure the tiny component of a function can work as designed. Different frameworks and tools can be used to run unit testing for different programming languages. In Ruby, one popular unit testing framework is Rspec, or Chefspec if you are writing Chef recipes. While writing Chef recipes, some low level commands(DOS commands or shell commands) need to be executed on the managed resource to perform actions or gather information. For example, lis...

   RUBY,UNIT TESTING,RSPEC,CHEFSPEC,SHELL_OUT     2016-11-11 00:14:46

  10 tools to make your shell script more powerful

Many people mistakenly think that shell scripts can only be run in command line. In fact shell can also call some GUI components such as menus,alert dialogs, progress bar etc. You can control the final output, cursor position and various output effects. Here we introduce some tools which can help you create powerful, interactive and user friendly Unix/Linux shell scripts. 1. notify-send This command can let you inform the process to send a desktop notification to users. This can be used to send ...

   shell,GUI,zenity     2013-04-05 08:50:41

  Here is what XcodeGhost author says

The first compiler malware in iOS was disclosed by Chinese iOS developers on Wednesday(Beijing time). The name of this malware is XcodeGhost as described by Alibaba researchers who released the analysis of this malware.  The malicious code is located in a Mach-O object file that was repackaged into some versions of Xcode installers. These malicious installers were then uploaded to Baidu’s cloud file sharing service for used by Chinese iOS/OS X developers. Xcode is Apple’s offic...

   IOS,SECURITY,XCODEGHOST,APP STORE,APPLE     2015-09-18 20:51:38

  How does MySQL handle DROP TABLE

A few days ago, when executing DROP TABLE in MySQL, all processes including DDL and DML were hung until DROP TABLE was completed. I am confused about this phenomenon. I have reviewed the source codes of MySQL to check how MySQL internally handle DROP TABLE. When user trigger DROP TABLE command: ########################MySQL SERVER drop table######################## /* Sql_table.cc  delete (drop) tables. */bool mysql_rm_table( )   /*   Execute the drop of a normal or temporary...

   MySQL,DROP TABLE     2012-09-24 11:34:05

  How to find which process a file is being written by in Linux?

Some people ask a file is being written by one process and they want to check this process, but they cannot find the process even with sof. This question is very common and there are many solutions, here we introduce a straightforward method. In Linux, each file will be stored on one device and of course there will be a relative inode, then we can use vfs.write to know who is writing the inode on one specified device continuously. Luckily there is inodewatch.stp in the installation package of s...

   Linux,process,file write     2013-03-16 21:44:35

  The world's first HTML5 SIP client

This is the world's first open source HTML5 SIP client (May 12, 2012) entirely written in javascript for integration in social networks (FaceBook, Twitter, Google+), online games, e-commerce sites... No extension, plugin or gateway is needed. The media stack rely on WebRTC. The client can be used to connect to any SIP or IMS network from your preferred browser to make and receive audio/video calls and instant messages. The protocol parsers (SIP, SDP...) are highly optimized using Ragel loo...

   HTML5,SIP,CLient,Google     2012-05-21 06:18:34

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