Top 10 UNIX and Linux System Programming Books- Best of Lot, Must Read

I have been sharing programming books in this blog for a long time, starting with core Java; I moved to other related technology, like Spring, Design patterns, Data Structure and Algorithms, etc. Today, I am going to share some of the best UNIX and Linux programming books. The list contains some of the must-read UNIX books from great writers like Sir Richard. Stevens, Sir Brain Kernighan, who has contributed so much to the development of the UNIX operating system. Most of the books on this list are timeless,  classic, and don't age with time, much like UNIX, which is around for the last 40 years, and I am sure it will be around for the next 40 years, or maybe forever.

How to send HTTP request using curl and wget command from Linux and UNIX? Example Tutorial

You can use either curl or wget command to send HTTP requests from UNIX or Linux operating system. Both commands allow you to send GET and POST requests, which means you can also call REST web services.  I have a Java web application, which runs on Linux and exposes WebServices. I was writing a UNIX script to download In some data from that web service when I hit by the question, how do I make an HTTP call from UNIX? What is the UNIX command should I use? If you are also facing the same problem, then you have come to the right ht place. Basically, you can use two UNIX commands to make the HTTP request, wget, and curl.

Top 5 Books to Learn Scala and Functional Programming - Best of Lot

Scala is one of the relatively new programming languages which encompasses best practices of many programming languages. The biggest strength of Scala is that it provides a beautiful blend of object-oriented programming and Functional programming. So, you can not only construct elegant class hierarchies for maximum code reuse and extensibility, but you can also implement their behavior using higher-order functions. It has a concise syntax with less ceremony, which also makes it ideal for scripting but doesn't underestimate its power. Like Java, Scala has also used for mission-critical applications by technical giants like Twitter, LinkedIn, and Intel.

10 Example of lsof commands in Linux and UNIX

It's been a long time since I have written anything on UNIX or Linux commands. Still, today, I'll talk about the lsof command, a utility command every system admin and developers love. The lsof command stands for list open file descriptors, and as the name suggests, it is used to find open files by the process. Since almost everything in UNIX are file, you can use lsof command to find an open regular file, a directory, a symbolic link, a special block file, an NFS mounted file, a socket stream, a shared library, a special character file, a regular pipe, a named pipe, an internet socket, a UNIX domain socket, and many others. I have mostly used it to find all the files opened by a particular process, which I will show you in the next section.

How to Enroll on Spring Professional Certification (VMware EDU-1202) and Schedule Exam

So, you have been preparing for Spring certification for quite a sometime, and now you feel you are ready to take the exam, and it's time to buy the Spring certification voucher and schedule your exam. In this article, I'll show you how to buy the Spring certification voucher online. But, before purchasing a voucher, I would like to remind you that the Spring certification (VMware EDU-1202) voucher is only valid for 90 days, after that it will expire. So, it's best to buy the voucher only if you are ready for the exam i.e. you have gone through several Spring Mock tests and practice tests given in Spring study guides and you are consistently scoring over 80% on them.

Do you Need to Pass OCAJP before taking OCPJP - Core Java Certification from Oracle

Even though we now have Java 11 certification, I know many Java developers who are going for Java certification like Java SE 8 Programmer 1 and 2, also known as OCAJP 8 and OCPJP 8 with exam code 1Z0-808 and 1Z0-809. Even though Oracle split Java certification into 2 after acquiring Sun Microsystem in 2010, there is still confusion among Java developers whether they need to pass just one OCAJP exam or both OCAJP and OCPJP exam to become a certified Java developer. Well, The short answer is Yes, if you want to become a Java certified engineer then you need to pass both OCAJP and OCPJP, but the long answer depends upon your situation, e.g. whether you hold any previous Java certification or not, which we'll discuss in the second section.

What is the best Book to Learn Java for C and C++ Programmer?

In the last 2 decades, many Java programmers started programming with C and C++, but the situation is changed now, you have more choices like you can choose Python, or you can even start with Java. It seems Academia prefers Python in the USA and Java in India, but there are still many programmers who know C and C++ and want to learn Java for one or other reasons. I often receive emails from my readers about book recommendation, and recently, a couple of them asked me to suggest the best Java books for C and C++ programmers. I can relate those beginners to myself because I have also gone through the same phase, but those days, the university textbooks are our only source to learn new things. We didn't have broadband, and unlimited access to the Internet and eBooks was not popular at that time, but things have changed.

How to Convert a Lambda Expression to Method Reference in Java 8?

If you have been coding in Java 8 then you may know that using method reference in place of lambda expression makes your code more readable, hence it is advised to replace lambda expression with method reference wherever possible. But, the big question is, how do you find whether you can replace a lambda with method reference? Yes, it's not that easy, especially if you have been using Java 8 only for a couple of months and struggling to get the functional programming concepts and idioms sorted in your head. Sometimes, IDEs like IntelliJ IDEA and Eclipse does offer some hints to convert lambda expression to method reference but it does make sense to learn the logic behind it, otherwise, it won't make sense.

The OCAJP 1Z0-808 - Best Books and Mock Exams for Java 8 OCA Certification

From the last couple of months, I have been helping a few developers to prepare for Java 8 associate certification with exam code 1Z0-808, also known as OCAJP 8. From my experience, both for preparing for Sun certification and helping other developers to get Java certified, I can say that two keys to be successful in Oracle Java SE certification are choosing an excellent study guide/course and buying one or two top quality mock exam simulators. When I say success, it doesn't mean just passing the exam but scoring above 90% because passing score 65% is not very difficult to achieve and anybody can pass OCAJP 8 by just a couple of month of practice but to score 90% and above is not that easy, you need to prepare and prepare hard.

How to Compare Date in SQL Server Query? Finding All Rows Between Two Dates

It's tricky to use dates in the SQL server query, especially if you don't have good knowledge of how DateTime type works in the SQL server. For example, one of the frequently asked SQL queries on the interview is to "select all rows where the date is 20151007?" How would you do that? Does the following SQL Query will work correctly

select * from table where date = '20151007'

It may or may not, it entirely depends on upon data in your table. When you only provide date part of a DateTime variable, it uses '00:00:00.000' for the time part.

Java 8 Certifications - Oracle Java SE 8 Programmer 1 (1Z0-808) - Latest OCAJP Exam (OCP 11 1Z0-815 and 1Z0-816)

Update: The latest version of Java SE certification is now OCAJP 11 (1Z0-815) and OCPJP 11 (1Z0-816) which is based upon Java 11 version. You can take these two exams to become a certified Java 11 developer, but if you already have an Oracle Certified Professional Java Programmer for the Java 6, 7, or 8 versions, then you can take the upgrade OCP Java 6, 7, and 8 to Java SE 11 Developer exam (Exam Code 1Z0-817). I don't have much detail, so I still keep this post as it is, but once I have got more information. I will also update this post. Today one of my readers asked about what is the latest OCPJP or SCJP exams available and is there a Java certification available for Java SE 9 and Java SE 10?

Why become a Certified Java Programmer? Does Oracle Certified Professional Earn more?

I have seen many Java programmers in doubt whether to go for Java certifications or not? Whether getting Java certified will help them to earn a better salary? or after becoming Java certified from Oracle will help them to get a Job. In this article, we will see what the benefits of getting Java certified are. I know higher income, better job prospects, and a better chance of promotion is at the top of the benefits of becoming a certified Java professional, but this certification provides much more value than that. Apart from all those tangible benefits, the most important thing is that you learn Java better, which help you everywhere like in your day job as well as on interviews.

Top 10 Java 11 Certification Mock Tests and Practice Tests [4 Free OCPJP 11 Sample Questions]

The latest Java certification is now out, the Java 11 Certification. Ever since Java 9 and Java10 were out, programmers were speculating that what will happen to Java certification now? Will, there is, be a new Java 9 certification or Java 10 certification? Will there be a new Java certification every 6 months, following the Java SE release cycle? Well, Thankfully, nothing of that sort happened; a new Java certification every six months would have been a crazy idea, not just for students and programmers but also to all the parties involved, including Oracle itself.  Now the big question is what has been changed in Java 11 certification, and should you go for OCAJP 8 or OCAJP 11 certification?

Entuware or Whizlabs? Which Exam Simulator Should you Buy for Java Certifications (OCAJP, OCPJP, and Others)?

I often receive queries from Java certification aspirants about exam simulators like whether should I go for Whizlabs or Enthuware, which one is better? If I have to buy just one exam simulator, which one would you recommend, Whizlabs or Enthuware? I thought to answer all those questions in a blog post and here you go. To be honest with you both of them are really high-quality test simulators and whichever you buy, you will do well on actual exams. But, as a programmer, I really like to analyze the situation, I compare pros and cons of each of them before I buy one of them. Since I have used both of them in the past I am sure about that in quality, they are neck to neck there, but here are couple of things which you can consider before buying Java certification simulator from Whizlabs or Enthuware

How to share your Programming Articles on Javarevisited for more Exposure

Hello, Friends,
I have been writing Java articles for a long time and one thing I have learned from that experience is that learning makes you a better Programmer and Software developer. It's also one of the important tips I have shared on how to become a better programmer article long back. It seems many people like that and contacted me about that but their main difficulty was that after writing one or two articles they get frustrated because no one was reading it. Well, I can understand but it takes a lot of time and effort to build a following. I am fortunate and really grateful that Java community has given me so much love and that's why I have decided to do my bit to promote and encourage every new Java programmer/writer/blogger to the best I can.

4 Ways to find Nth highest salary in SQL - Oracle, MSSQL and MySQL

One of the most common SQL interview questions is to find the Nth highest salary of employees, where N could be 2, 3, 4 or anything e.g. find the second highest salary in SQL. Sometimes this question is also twisted as to find the nth minimum salary in SQL. Since many Programmers only know the easy way to solve this problem e.g. by using SQL IN clause, which doesn't scale well, they struggle to write the SQL query when the Interviewer keeps asking about the 4th highest, 5th highest and so on. In order to solve this problem effectively, you need to know about some key concepts like a correlated subquery, window functions like ROW_NUMER(), RANK(), and DENSE_RANK(), etc. Once you know the generic logic to solve this problem, you can tackle all those variations by yourself.