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  Deep Understanding of ReentrantLock: Unlocking the Mysteries of Java Concurrent Programming

ReentrantLock introduction ReentrantLock is a class in the Java concurrent package, java.util.concurrent.locks, and is an implementation of the Lock interface. As its name suggests, it is a reentrant mutual exclusion lock. A mutual exclusion lock is a synchronization tool used to protect shared resources, ensuring that only one thread can access the resource at a given time. Reentrant means that a thread can acquire the same lock multiple times without causing a deadlock. This lock provides some...

   JAVA,REENTRANTLOCK,CONCURRENCY,MULTITHREADING     2023-05-22 08:01:13

  How Query Optimizer Works in RDBMS

In a previous post, we discussed how the various relational operators are implemented in relational database systems. If you have read that post, you probably still remember that there are a few alternative implementations for every operator. Thus, how should RDBMS determine which algorithm (or implementation) to use? Obviously, to optimize the performance for any query, RDBMS has to select the correct the algorithm based on the query. It would not be desirable to always use the same algori...

   DATABASE,DATABASE DESIGN,DATABASE OPTIMIZATION     2019-04-20 07:26:32

  37 powerful Linux shell commands

To work on Linux platform, you cannot avoid using shell commands to complete some tasks. These tasks can be as simple as list files in some directories or find some text in some file, or can be as complex as monitoring processes. In this post, we will share 37 powerful Linux shell commands.   Task Commands 1 Delete file with 0 byte(empty file) find . -type f -size 0 -exec rm -rf {} \;find . type f -size 0 -delete 2 Check process memory consumption ps -e -o "%C : %p : %z : %a"|sort -k...

   Linux command,List     2013-09-16 07:47:16

  How DNS lookup works

When accessing a website, a domain name would be needed normally. To get to the actual web server, the domain name must be mapped to an actual IP address and the IP address will be used to reach the web server. The process of finding the IP address from a domain name is called DNS lookup.  How does DNS lookup work? There are tons of domain name and IP address around the world, there must be some well-designed architecture to support fast lookup. This post will explain how this works. DNS Se...

   DNS,DNS LOOKUP     2022-09-09 23:11:03

  Resolving SVN error "Error validating server certificate for..."

When using SVN to connect secure server, the server needs to send its certificate to the client for verification. In some cases, the certificate sent by the server is not a trusted certificate, the client may choose to trust the certificate if the server is target server for sure.  But users may get "Error validating server certificate for 'https://...'" the next time when they try to connect to the same secure server even if they specified "p" the first time when they are prompted to accep...

   SSL,SVN,SVN.SSL.SERVER     2016-06-27 07:36:49

  Connect to SQLite using Go on Windows

In software development, it's often necessary to test and validate logic using a lightweight and easily manageable database system. SQLite, with its minimal setup and zero configuration requirements, is an excellent choice for such scenarios. Leveraging the simplicity and efficiency of SQLite for testing purposes can significantly streamline the development process. In this guide, we'll explore how to seamlessly connect to SQLite using Go on Windows, empowering developers to efficiently test the...

   WINDOWS,TUTORIAL,GOLANG,SQLITE3     2024-02-11 20:58:12

  Latest PHP patch cannot fix the bug

On Wednesday(2012-05-02), a remote code execution vulnerability in PHP was accidentally exposed to the Web, prompting fears that it may be used to target vulnerable websites on a massive scale. The bug itself was traced back to 2004, and came to light during a recent CTF competition.A CERT advisory on the flaw explains: “When PHP is used in a CGI-based setup (such as Apache's mod_cgid), the php-cgi receives a processed query string parameter as command line arguments which allows com...

   PHP,bug,patch,bypassed     2012-05-08 11:20:56

  Publish Your Go Package on pkg.go.dev

go.dev is a site where various resources for Go developers are shared, such as “Get Started”, Tutorial, Packages (pkg.go.dev), and all the official blogs. Among them, Packages is where I visit most, which allows free access to all the open-source Go packages submitted by communities including the native Golang packages. Thanks to all the contributors, I enjoy the great benefit, and sometimes I want to be a contributor myself. Let’s submit a “complete” package t...

   GO.DEV,PUBLISH PACKAGE,GOLANG     2022-06-12 00:31:20

  Programmer professionalism

Programmer is a lifetime occupation. But first, as a programmer you need to love programming, rather than just an occupation to achieve other goals in life.Now if you plan to spend decades of life on programming, then you should continue to think about what is more efficient. In other words, how are you different from who you were a decade ago and how will you be better than who you are now a decade later?In my opinion, a programmer, regardless of his work, should improve himself in three aspect...

   Programmer, Idea     2012-12-10 12:05:24

  Advantages Associated with Semantic SEO Searches

Today, all businesses are aware of the fact that SEO is an integral part of their online endeavors. However, some of them do not really know or understand the way SEO works and how things are changing in the SEO landscape. Do you have any idea about some positive effects of SEO and how this specific shift has affected the way people search online and exactly how search results would be ranked? SEO has been there for decades now. However, only since the year 2000 onwards, Google has proactively ...

   ALGORITHM,SEO,SEMANTIC SEO,ADVANTAGEST,HUMMINGBIRD     2018-08-14 01:02:16