SEARCH KEYWORD -- SYSTEM

  Java Concurrency Basics: CountDownLatch and CyclicBarrier

CountDownLatch CountDownLatch can be used in synchronizing behavior among threads, it makes one or more threads wait for some actions in other threads to be completed. It has a property count which defines how many countDown() need to be called before other threads which called await() to be waked up.  When a thread calls CountDownLatch.await(), the thread will be blocked until the value of count becomes 0. The initial value of count can be specified when creating the CountDownLatch instanc...

   JAVA,JAVA CONCURRENCY,COUNTDOWNLATCH,CYCLICBARRIER     2018-03-25 07:02:40

  C++ for the Real-Time Web

C++? Why on Earth? C++ seems like one of the least likely languages to write a web application in. C++ is associated with complexity, both with language design and the need to manually manage memory. Programming in C++ unleashes a whole class of bugs associated with memory corruption and memory allocation. This is a trade off for giving more power to the developer along generally being much faster than equivalent programs in languages such as Python or Ruby. Real-time Web as a Use Case Making...

   C++,Web development,Real time     2012-01-30 06:00:20

  Why using + to concatenate string in Java loop is not a good option

String concatenation is a common operation in Java programming. It is to concatenate multiple strings into a single string. Java provides a String class which is an immutable class which means the object cannot be mutated once instantiated. Once a String object is instantiated, its properties cannot be changed anymore, so when concatenating strings, it's actually create a new String instance to store the concatenated string values. For example, below is a simple string concatenation example. Str...

   JAVA,STRING,JAVA 8     2019-01-18 22:07:12

  Fix issue where no Java virtual machine found when launching Eclipse

In cases where a new Eclipse is installed or the location of the Java virtual machine binaries has been changed, you may face issue when launching Eclipse. The error would look like. And if you go to the location specified in the error message, there is no such path indeed.  And when clicks OK, the program just exits. The issue here is that it tries to find the java.exe binary and launch the program but it failed to locate it and hence exits. To fix this, you first need to ensure you have...

   ECLIPSE,JAVA,LAUNCH,ECLIPSE.INI     2019-09-07 05:31:27

  SSL in PHP for WAMP

Sometimes when we need to use email service provided by WAMP, we need to use some remote mail server such as Gmail. In Gmail, if we want to use the SMTP server to send email and want to use port 465, then the SSL connection should be setup. But by default in WAMP, the ssl is not usable. So to allow use SSL, what we should do is go to system tray and click PHP->PHP Extensions->php_openssl. Then now you can use Gmail to send email easily....

   Email,Php,Gmail,SSL,WAMP,SMTP     2011-03-24 11:56:37

  What’s the waiter doing with the computer screen?

When Richard Gatarski and a few friends wanted to dine in the Swedish city of Norrköping a few weeks ago, they booked a table at a downtown Italian restaurant that seemed nice. When they arrived, they were greeted by the headwaiter, who asked if they had a reservation. Richard confirmed, and the headwaiter looked at his computer screen. ”Gatarski? Hm, let’s see .. yes, there’s your reservation. Welcome!” The headwaiter then picked up what Richard first thought m...

   Waiter,Computer screen,Touch     2012-03-12 11:07:01

  How does computer boot up?

The whole boot process of computer can be summarized in 4 phases. 1. BIOS In the 70's  read-only memory(ROM) was invented. The boot program is written into ROM, the first thing the computer does is to read and execute this program when it's powered on. The program in this chip is called "Basic Input/Output System" (BIOS). 1.1 Power-On Self-Test The BIOS will first check whether the computer hardware can fulfill the basic conditions for booting up, this process is called Power-On Self-Test...

   Computer, boot, partition     2013-02-23 23:19:47

  Java vs F#

Dr Cliff Click of Azul Systems, specialists in manycore JVM systems, recently published a blog post about the performance of Java compared primarily to C and C++ but also discussing C# and .NET. Three of Cliff's comments are of particular interest:Under the heading "Places where C/C++ beats Java for obvious reasons":"Value Types, such as a 'Complex' type require a full object in Java." - Dr Cliff ClickWhat Cliff forgot to mention is that .NET also provides value types and a far more compell...

   Java,F#,Performance,JVM     2012-03-07 05:07:31

  Amazon is a good company but doesn't have the best business model

Public opinion about a company is usually based on its performance. If it performs well, people will praise it, otherwise people will blame it. In 1999, Apple was still a broken apple(Steve Jobs's talent and effort was paid off yet). Public opinion about Apple was the closed model caused Apple's failure. They built hardware themselves, developed software themselves and delivered service themselves, this is certainly not sustainable. But Steve Jobs let everyone see this new model. In order to con...

   Business model,Amazon,Apple, Microsoft     2013-07-02 11:34:45

  What is Hystrix and How does Hystrix work

Background In distributed systems, there is one effect where the unavailability of one service or some services will lead to the service unavailability of the whole system, this is called service avalanche effect. A common way to prevent service avalanche is do manual service fallback, in fact Hystrix also provides another option beside this. Definition of Service Avalanche Effect Service avalanche effect is a kind of effect where the service provider fails to provide service which causes t...

   AVALANCHE EFFECT,HYSTRIX,DISTRIBUTED SYSTEM     2019-02-04 06:00:38

RECENT