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SEARCH KEYWORD -- INFINITE LOOP

  Why accessing Java HashMap may cause infinite loop in concurrent environment

HashMap in Java is frequently used to handle key/value pairs. But it is not a good candidate to be used in concurrent environment where ConcurrentHashMap should be used instead. If used in concurrent environment, it may cause lots of unexpected behavior even including make the program getting into an infinite loop situation. To understand how this can happen, let's first discuss how HaspMap works internally. In this post we will use implementation of HashMap before Java 8 as example, Java 8 prov...

   JAVA,HASHMAP,INFINITE LOOP     2020-03-29 01:47:00

  Converting Decimal Fractions to Binary

Converting Decimal Fractions to Binary In the text proper, we saw how to convert the decimal number 14.75 to a binary representation. In this instance, we \"eyeballed\" the fractional part of the binary expansion; 3/4 is obviously 1/2 + 1/4. While this worked for this particular example, we\'ll need a more systematic approach for less obvious cases. In fact, there is a simple, step-by-step method for computing the binary expansion on the right-hand side of the point. We will illustrate the metho...

   Decimal,Fractional,Binary     2011-03-19 06:45:35

  Some tricks and tips for using for range in GoLang

GoLang provides two major ways to loop through elements of array, slice and map. They are for and for range. Many people find that for range is very convenient when don't care about the index of the element. In this post, some tricks and tips would be talked about regarding for range. 1. Loop and get pointer of each element Assume there is a code snippet like below which is to get the pointer of each element in an array and create a new array with the corresponding pointer. arr := [2]int{1, 2} r...

   POINTER,FOR LOOP,GOLANG,FOR RANGE     2020-03-08 01:07:00

  Why can System.out.println be used to exit while loop

Let's first take a look at one simple Java thread code snippet which is supposed to exit the while loop after the first loop run. public class StopThread { private static boolean stopRequested; public static void main(String[] args) throws InterruptedException { Thread backgroundThread = new Thread(new Runnable() { @Override public void run() { int i = 0; while (!stopRequested) { i++; } } }); backgroundThread.start(); TimeUnit.SECONDS.sleep(1); stopRequested = true; } } But the tr...

   JAVA,THREAD,VOLATILE     2018-12-21 19:25:54

  Deep clone of JavaScript object

In JavaScript world, it's frequently seen object clone. Normally when creating a clone of an object, it's only the reference being cloned but not all contents. In some scenarioes, it's desired to clone all the content instead of just the reference such that any change made to the cloned object will not change the original object. Differences between shallow clone and deep clone can be as simple as: Shallow clone : Only the object reference is cloned but not the content Deep clone : Clone all co...

   JAAVSCRIPT,DEEP CLONE,DEEP COPY,SHALLOW CLONE,SHALLOW COPY     2016-10-31 00:27:24

  Some famous product release venues

About product release conference, you must remember Apple Worldwide Developers Conference(WWDC), right? But do you remember where the conference is held? Actually, when companies release new products, they will hold some kind of conferences or sessions to introduce their products. But does anyone know what are the places where these conferences are held? Here geekpark summarized some product release places for us. 1. Moscone West Convention Center Moscone West Convention Center is the biggest co...

   Conference, Place,Product release     2012-10-11 20:32:22

  Highly efficient PHP code writing

Next are some tips for writing highly efficient PHP codes. They are described below: 0. Use single quote to replace double quote, this will be better since PHP will serach for variables in double quoted strings. Note, only echo can do this; 1. If we can define methods of a class as static, then do it. It will increase access speed by 4 times; 2. $row["id"] is 7 times faster than $row[id]; 3. echo is faster than print, and also use echo's multiple parameter format such as echo $str1,$str2 inst...

   PHP,Code writing,High efficient,Tips     2011-07-23 12:35:50

  Coming full circle

Experts often end up where they started as beginners.If you’ve never seen the word valet, you might pronounce it like VAL-it. If you realize the word has a French origin, you would pronounce it val-A. But the preferred pronunciation is actually VAL-it.Beginning musicians play by ear, to the extent that they can play at all. Then they learn to read music. Eventually, maybe years later, they realize that music really is about what you hear and not what you see.Beginning computer science stu...

   Expert,Life cycle,Work,Begin,End,Cycle     2011-10-30 12:18:33

  The tic-tac-toe game with Python

In this tutorial, we will show how to build a tic-tac-toe game with Python. We will use functions,arrays,if statements,while statements, for loops and error handling etc. First, we need to create two functions, the first function will display the borad of the game: def print_board(): for i in range(0,3): for j in range(0,3): print map[2-i][j], if j != 2: print "|", print "" Here we used two for loops to loop through the map, this map is...

   Python,Tic-Tac-Toe     2013-07-30 02:49:09

  Select top 3 values from each group in a table with SQL

Yesterday, my friend Liu Bing asked me a question about how to select top 3 values for each person in a database table using SQL. I think this question is interesting and it deserves some thoughts. Here I record down how to solve this issue. Assume we have a table which has two columns, one column contains the names of some people and the other column contains some values related to each person. One person can have more than one value. Each value has a numeric type. The question is we want to se...

   SQL,Correlated query,top 3     2013-05-23 03:21:25

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