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  What does super.clone() do?

Object class has a protected clone() method declared to make it possible for all classes make a clone of itself when needed. The clone() is often used when a new instance of the class is needed while at the same time to maintain the same state as the original object. Any class which wants to have clone enabled has to implement the marker interface Cloneable. If a class which implements Cloneable doesn't override the Object.clone() method, the Object.clone() method will be called to just make a b...

   Cloneable,super.clone(),clone,Java     2015-01-07 05:25:52

  Understand Virtual DOM

With the popularity of React, the internals and implementation of Virtual DOM has becoming top discussed topic in tech communities and interviews. This post will give an introduction of Virtual DOM and how to implement a simple Virtual DOM logic. How to understand Virtual DOM In early days, front end developers would update a webpage view based on the data status change(usually after making AJAX call). But it brings performance penalties when there is frequent update as it would cause page reflo...

   JAVASCRIPT,DOM,VIRTUAL DOM     2019-12-07 23:43:04

  Error handling in GoLang

Error handling is one of the must talked topics for any programming language. The program would be more reliable and stable if errors are handled properly and timely. Each programming language has its own way to handle error, this applies to GoLang as well. This post will discuss more about GoLang's error handling mechanism. Error handling Before talking more about GoLang's error handling, we can see how different programming languages are handling errors. C's error check The most direct way of ...

   GOLANG,ERROR HANDLING,FLUENT INTERFACE     2021-03-06 21:36:08

  Why cannot compare double values directly for equality?

A question in PHP: Get some value from the database and use floatval() to convert it to floatint point value, then compare it with another value which is also converted to floating point value with floatval(). These two values are the same when using var_dump() to output, the two outputs are float(8.87), they are the same. But when comparing them for equality, the result is weird., they are not equal. Why?To analyze this question, we need to start with PHP data types. PHP uses weak types. In PHP...

   PHP,floating, precision,compare,equality     2012-06-27 09:01:36

  The Wasteful Legacy of Programming as Language

A few years ago I visited a friend who is a graduate student in linguistics. After some time he asked me if I was aware of the work by Chomsky on formal languages. I told him that yes, Chomsky work was a basis for much of the developments in theoretical computer science. More than that, I was glad to learn that there was something technical that I could share and discuss with other people in linguistics. At the time I found this was just a great coincidence. It was only recently, though, t...

   Programming language,Human language,Chomsky     2011-11-28 10:36:34

  Advantages and disadvantages of GoLang

GoLang is a strong typed language which means it is less flexible than interpreted languages by nature. But Go provides Any type(interface) and Reflect mechanism which make the language very close to interpreted languages on flexibility. More and more people start to learn GoLang. This post is mainly for listing down some of the advantages and disadvantages of GoLang. Advantages Performance(Machine code) GoLang is a compilation language which can be compiled to machine code and the compiled bina...

   GENERICS,GOROUTINE,GOLANG,DISADVANTAGE,ADVANTAGE     2018-11-10 20:46:45

  Beginners guide to Linux directory structure

Have you ever looked in your / directory, you’ll see a lot of directories. Here we are presenting beginners guide to linux directory structure explaining what they mean and what are the contents of these directories.Screenshot of contents of root directory: /This is called root partition. All files and directories start with root partition. Write privileges under this directory are avaible with root user only. Not to confuse it with root user’s home directory, know the ...

   Linux,File system structure,Beginner's guide     2012-04-20 12:19:32

  Smuggling data in pointers

While reading up on The ABA Problem I came across a fantastic hack.  The ABA problem, in a nutshell, results from the inability to atomically access both a pointer and a "marked" bit at the same time (read the wikipedia page).  One fun, but very hackish solution is to "smuggle" data in a pointer.  Example:#include "stdio.h"void * smuggle(void * ptr, int value){  return (void *)( (long long)ptr | (value & 3) );}int recoverData(void * ptr){  return (long long)ptr &...

   C,Pointer,Bit,Data,Atomic,Smuggle     2011-11-14 08:15:59

  What are some lesser known but useful Unix commands?

A few that come to mind, some less known, some more: xargs or parallel: run things in parallel, with lots of options sed and awk: more well-known but still super useful for processing text files, and faster than Python or Ruby m4: simple macro processor screen: powerful terminal multiplexing and session persistence yes: print a string a lot cal: nice calendar env: run a command (useful in scripts) look: find English words (or lines in a file) beginning with a string cut and paste and join: data...

   Linux,Unix,Command,Less used     2011-12-27 09:27:49

  XMLHttpRequest Level 2 user guide

XMLHttpRequest is a web browser interface, it makes it possible for JavaScript doing HTTP(s) communication. Microsoft's IE5 first introduced XMLHttpRequest, because it's so useful that many other browsers also adopted this. AJAX came to the front since. However, this interface is not standardized, implementation among different browsers is different, with the emerging of HTML5, W3C is considering to standardize this interface. In February 2008, they proposed a XMLHttpRequest Level 2 draft. This ...

   XMLHttpRequest, progress, upload, binary data     2012-09-19 11:51:50

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