Generate a unique N letters word sequence (by using relationship between Factoradic base system and Lexicographic Permutation Order of a String)

Lets say that you want to generate a unique 3 letters code sequence to be used as a primary key for some data recodes. Also let assume that you are allowed to use alphanumeric characters. For example:

• ABC ->  Data Recored 1
• CBA -> Data Recored 2
• Z1T  -> Data Recored 3
• R39  -> Data Recored 4
• etc ..

The Power of Invisible reCaptcha from Google and How to Integrate it With Your Web Application (Spring Boot)

In this post I will talk about the exciting new version of Google reCaptcha, the invisible reCaptcha (well, almost invisible)! Also, I will demonstrate how to integrate it with a typical Spring Boot web app and then do some customizations to better control its behavior.

Embed Tomcat 8 Maximum cache size issue in Spring boot 1.4

If you are running Spring boot with an embed tomcat 8, you might you see the following error when you try to run you app:

consider increasing the maximum size of the cache 

How to stop node.js server?

You  can run the node server by typing:

node server.js

But how to stop it ? typing command CTRL+C  might not kill the process and then end up with error like the following 

Running a Java Program as a daemon (Background service) on *nix systems

How to run a Java Program as a daemon (Background service) on *nix systems?

Ever needed to run a Java program as a daemon (background service) on your *nix server? All you want is to run some basic operations such as start/stop/restart? then are not a lone.

Using Regex with positive lookahead in Oracle

There are times where you need to query data from the database that matches a particular regular expression. Depending on your requirements, you might need to use a positive look ahead in your regex.

Measuring Password Strength (Bits of Entropy)

How to measure password Strength ?

Being in the momentum of “the internet of things“ everyone has to have many online accounts nowadays. With all these accounts, users and applications are always in a race to protect their private data from piracy.