Thursday, April 26, 2018

How to Find K Missing Numbers in Integer Array With Duplicates in Java?

It's been a long time since I have discussed any coding or algorithm interview questions, so I thought to revisit one of the most popular array based coding problem of finding missing numbers in given array. You might have heard or seen this problem before on your programming job interview but there are a lot of different versions of increasing difficulty levels which interviewer normally use to confuse candidate and further test their ability to adapt to frequent changes. In the past I have demonstrated how to find the missing number in a sorted array as well on the unsorted integer array in Java using BitSet (see here), but, with just one missing number and without any duplicates.

Wednesday, April 25, 2018

Top 10 Java and Web Development Courses to Learn in 2018

Hello guys, I am sure you all have made your goals and resolutions for this year e.g. what to learn in 2018. If you haven't then check out my post 10 Things Java programmer should learn in 2018 for some ideas. If you have already made your goal then it is time to think about how you are going to achieve it. For example, my top 3 goals in 2018 are to learn JDK 9, Spring 5, and Spring Security 5 but how am I going to learn them? Well, I like books and online courses and that's why I have been searching for some good courses on JDK 9 and Spring 5. Luckily there are some available in Udemy and the best part is that they are currently running a New Year Sale event where every single course is priced just $10, Yes you heard it right, just $10.99, even for a course whose original price is $200.

Sunday, April 22, 2018

Top 5 Spring Cloud Courses for Java Developers to Learn Online - Best Of Lot

Hello guys, if you are learning Spring Cloud for developing cloud-based Java application and looking for some good resources to start with e.g. online courses and books then you have come to the right place. In this article, I am going to share some of the best courses to learn Spring Cloud and develop a cloud-based application in Java. One of the common question when it comes to learning a new technology is how to start? I was a big fan of books earlier but nowadays I personally like to start with an online course to learn things.  It works better because you gain a lot from instructor's experience and you also have a chance to ask questions to the instructor.

Saturday, April 21, 2018

2 Ways to Setup LDAP Active Directory Authentication in Java Spring Security Example Tutorial

LDAP authentication is one of the most popular authentication mechanism around the world for enterprise application and Active directory (an LDAP implementation by Microsoft for Windows) is another widely used LDAP server. In many projects, we need to authenticate against active directory using LDAP by credentials provided in the login screen. Sometimes this simple task gets tricky because of various issues faced during implementation and integration and no standard way of doing LDAP authentication. Java provides LDAP support but in this article, I will mostly talk about spring security because of it's my preferred Java framework for authentication, authorization, and security related stuff.

Thursday, April 19, 2018

Does Pivotal' Spring Certification helps in Job and Career? 5 Reasons to Become a Certified Spring Developer

One of the frequently asked question among Java and Spring developer is whether Spring certification is valuable? or does Spring Certification help you in Job and Career? These questions are not very different from what Java developer ask about Oracle's Java certification (see here). The short answer to these question is Yes, Spring Certifications are very valuable and it not only provides Industry recognition for your knowledge, experience, and skill but also set you apart from the millions of Java and Spring developer who are not certified. Of course, as with any certification, the most valuable part, apart from recognition is the learning process and this is true for Spring certifications as well.

Spring Security Concurrent Session Control Example Tutorial - How to limit number of User Session in Java JEE Web Application

If you don't know, Spring security can limit the number of sessions a user can have. If you are developing a web application especially a secure web application in Java JEE then you must have come up with the requirement similar to online banking portals have e.g. only one session per user at a time or no concurrent session per user. Even though you can also implement this functionality without using spring security but with Spring security, its just piece of cake with coffee :).  You just need to add a couple of lines of XML in your spring security configuration file and you are done. In order to implement this functionality, you can use the <concurrency-control> tag.