Permutation is a very basic and important mathematic concept we learned in school. It has very practical applications in real world. For example, in football.In simple, permutation describes all possible ways of doing something. For example, there are six permutations of the set {1,2,3}, namely: (1,2,3), (1,3,2), (2,1,3), (2,3,1), (3,1,2), and (3,2,1). In general, for n items, there are n! number of permutations to arrange these items. How can we implement this algorithm in programming programming language such as Java? Below is a simple code snippet which uses the recursive method. It's quite...

In our previous tutorial, we have explained how to generate CSR which can be sent to CA for generating a signed certificate. In this tutorial, we will explain how to generate the signed certificate from CSR in Java. We will not use an actual CA but a self-signed certificate to act as a CA certificate.Since the CSR contains the subject information where a certificate needs to be generated and signed for. The key here is to extract the subject information from the CSR and then set it as the subject of the newly generated certificate.The source code can be found below which has a complete example...

Java is one of the top 3 programming languages in the world. It can be used to develop both web applications and desktop applications and more importantly it is cross platform--write once, run everywhere. Also, it's easy to pick up. If you want to be a Java developer, please get to ask yourself whether you know below listed topics.This list is summarized by Vivek Vermani, a Senior Java Developer:For a Core Java Developer , Ffollowing topics should be good.OOPs ConceptsAbstract Classes and InterfacesConstructors and initialization orderFile IO and SerializationCollections - List , Map , SetAcce...

While launching any web application, a development company faces a challenge that is choosing the programming language for developing it. Though, there are many options available for companies to deliver app solution to businesses, such as .net, C++, Python, PHP, Ruby, and their derivatives; still many believe that java can be a good choice for development of apps. A java development company can make amazing app solutions by leveraging their development team’s skills and expertise. But the company also faces other challenges that will be discussed further in the post. Fig- Showing m...

If you’re one of those hipster programmers who loves Clojure, Ruby, Scala, Erlang, or whatever, you probably deeply loathe Java and all of its giant configuration files and bloated APIs of AbstractFactoryFactoryInterfaces. I used to hate all that stuff too. But you know what? After working for all these months on these huge pieces of Twitter infrastructure I’ve started to love the AbstractFactoryFactories.Let me explain why. Consider this little Scala program. It uses “futures”, which are a way to schedule computation to be done in parallel from the main flow of a pro...

Security has become a vital concern in most of the online transactions nowadays. Lots of the world's most popular websites have adopted security protocols to transfer data, especially sensitive data. These security protocols including SSL/TLS which are using the private/public key exchange mechanism to establish secure connections. The private/public key cryptography is a really important invention and it allows data to be transferred securely and solves the big problem of transferring symmetric key securely over Internet at the same time. Because of this characteristic, private...

The original Java 9 planned release date is March 2017. But latest source shows that Java 9 release will be delayed again to July 2017. It's four months later than the planned date.Oracle Chief Architect of Java Platform group Mark Reinhold proposes this new release date in a message sent on the OpenJDK mailing list. Despite this progress, at this point it's clear that Jigsaw needs moretime. We recently received critical feedback that motivated a redesignof the module system's package-export feature [5], without which we'dhave failed to achieve one of our main goals. Ther...

CountDownLatchCountDownLatch 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 instance. Every time when CountDownLatch.countDown() is called, the value of count will decrease by 1 until t...