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5 Free DevOps Courses to learn Jenkins, Docker, and Kubernetes Online

Hello guys, you might have heard about DevOps and all the attention it is getting now. The DevOps is a new phenomenon and there is a mad race among senior developers to become a DevOps engineer. Well, I am not one of them as my passion is for becoming a software architect but I have certainly spent some time learning DevOps just to increase my knowledge of the field as I strongly believe in the phrase, jack of all and master of one :-). In DevOps world, tools matters a lot and whole of the DevOps phenomenon to create an automated pipeline for delivering a quality software heavily relies on cleaver uses of tools like Maven, Jenkins, Docker, Kubernetes, and others.

Java 8 Optional Example - isPresent(), OrElse() and get()

The Optional class in Java is one of many goodies we have got from the Java 8 release. If you use correctly, Optional can result in clean code and can also help you to avoid NullPointerException which has bothered Java developer from its inception. Even though many of us have used null to indicate the absence of something, the big problem is that if you call a method or access a field on the null object (except static fields), you will get a NullPointerException and your whole program may crash. The bigger problem is to find the faulty code or root cause because NullPointerException only indicates the line when you try to access field or variable from a null object but how does that null is get created on the code is unknown.

How to Remote debug a Java Program in Eclipse IDE

The remote debugging of Java program is an ultimate tool in the arsenal of a Java developer, which is often become the last and only tool to investigate a bug on a Java application running on remote host e.g. on Linux server or Windows server. Almost all major Java IDE provides remote debugging like NetBeans, Eclipse, and IntelliJ IDEA, but I mostly use Eclipse for Java coding and so it's my preferred tool to remote debug a Java program. In order to set up remote debugging in Eclipse, you need to do a couple of tasks e.g. you need to start your JVM with debugging parameters or arguments and then you need to create a "remote debug configuration" in Eclipse IDE itself.

How to sort an Array in descending order in Java - Example

Sorting an array is one of the common tasks in Programming and you have many algorithms to sort an array like QuickSort, MergeSort which provides O(NLogN) time performance and Bucket Sort, Counting Sort and Radix Sort algorithms which can even sort some array in O(N) time. But, you hardly need to code these algorithms by hand when it comes to writing real code. The Programming language you will use already have tried and tested implementation for those algorithms and that's what you will learn in this article. In Java Programming language, it's easy to sort an array, you just need to call the Arrays.sort() method with a Comparator which can sort the array in the order you want but it highly depends upon which type of object is stored in the array.

Java 8 Map Function Examples

The map is a well known functional programming concept which is incorporated into Java 8. Map is a function defined in java.util.stream.Streams class, which is used to transform each element of the stream by applying a function to each element. Because of this property, you can use map() in Java 8 to transform a Collection, List, Set or Map. For example, if you have a list of String and you want to convert all of them into upper case, how will you do this? Prior to Java 8, there is no function to do this. You had to iterate through List using a for loop or foreach loop and transform each element. In Java 8, you get the stream, which allows you to apply many functional programming operators like the map, reduce, and filter.

5 Free Eclipse and JUnit Online Courses for Java Developers

Both Eclipse and JUnit are two of the essential tools for Java Developers. Eclipse is a Java IDE, Integrated Development environment which allows you to code, run and debug Java program from a single window, while JUnit is a unit testing library which allows you to test your Java code automatically. You can write JUnit tests and then you can run them automatically using Maven or Gradle plugin at build time. You can further automate your build using Jenkins which means your Unit test will run continuously and automatically, reporting any break at the earlier possible opportunity.

Top 10 Java 8 Stream and Functional Programming Interview Questions Answers

The JDK 8 release has changed the way we write Java. With new functional programming idioms and a powerful Stream API, most of the new Java code is written in functional style. This also means that Stream and Functional programming related questions are increasing on Java interviews. If you are not familiar with Java 8 changes then it's difficult to crack a Java interview nowadays. Though it's not stated anywhere most of the companies, particularly Investment banks like Barclays, Citi, and Goldman Sachs now expect Java developers to know at least Java 8, which is also good right? Java 11 is already out and we are looking forward to Java 12 in a couple of months, it makes sense to know at least Java 8 changes.

Top 5 Free Android App Development Courses for Programmers

Hello guys, Happy New Year 2019. I am sure you all have made your goals and started planning on how to achieve them. If you are passionate about creating mobile games and applications and want to learn how to develop Android apps or want to become an Android application developer then you have come to the right place. In this course, I am going to share some of the best and free Android development courses for Java programmers and others. You might know that earlier Java was the only language which is used to create Android applications but since last year, Google has announced Kotlin as the official language for Android app development which means you can use either Kotlin or Java to create Android apps.

How Binary Search Algorithm Works - Java Example Without Recursion

The binary search algorithm is one of the fundamental Computer Science Algorithms and used to search an element in a sorted input set. It's much faster than the linear search which scans each and every element and improves performance from O(n) to O(logN) for searching an element in the array. In order to perform the binary search, you need a sorted array, so you can either ask the user to enter array in sorted order or you should sort the array before performing the binary search. It's also one of the popular algorithms on Programming Job interviews. Interviewer often asks candidates to implement binary search algorithm by hand in their favorite programming languages like Java, C++, Python. or JavaScript.

Insertion Sort Algorithm in Java with Example

Insertion sort is another simple sorting algorithm like Bubble Sort. You may not have realized but you must have used Insertion sort in a lot of places in your life. One of the best examples of Insertion sort in real-world is, how you sort your hand in playing cards. You pick one card from the deck, you assume it's sorted, and then we insert subsequent card in their proper position. For example, if your first card is Jack, and the next card is Queen then you put the queen after Jack. Now if the next card is King, we put it after the queen, and if we get 9, we put it before jack. So if you look closely, Insertion sort is a perfect sorting algorithm to insert a new value into an already sorted array. That's why the best-case complexity of insertion sort is O(n), in which case you can just insert a new number in the already sorted list of integers.

5 Free Courses to Learn C# Programming Online

Many people underestimate the power of C# and never think highly of it when they talk about programming languages, but the truth is that C# is one of the popular programming languages of today's world, just behind JavaScript, SQL, and Java on StackOverFlow's Developer Survey for last a couple of years. There are a lot of jobs and opportunity available for experienced C# developers. It's one of the important languages for developers working with Microsoft technologies like Windows and SQL Server. It is also one of the most popular programming languages for developing desktop GUI, surpassing Java Swing completely in last a couple of years. I have seen many big investment banks switched from Swing to C# for their GUI development work.

Java Program to Reverse an Array in place? Fastest Example

It's relatively easy to reverse an array if you have the luxury to use another array, but how would you reverse an array if a temporary buffer is not allowed? This is one of the testing array interview questions, which often proved tricky for Java and other beginner Programmers. But, don't worry, I'll tell you how you can solve this problem without losing your cool. Well, you can also reverse an array in place without using an additional buffer. If you know how to access array elements and how to loop over an array in Java using traditional for loop, you can easily solve this problem without using additional space or in-place as described in many Algorithms books and courses, and on Coding interviews.

5 Free Courses to Learn Swift Programming for iOS Developers

Hello guys, how are you doing this lazy Saturday? You might be thinking, as a Java developer why I am suggesting you learn Swift, but the truth is that I am not suggesting you abandon Java and join Swift, I am suggesting you join Swift if you want to develop iOS applications. We all use Apple's product and we love them, I have used iPod, iPhone, iPad, Apple Watch, and even MacBook and every time I use their product I just say wow and Swift are no different from that. It's a programming language from Apple so you will find all the features which makes Apple product great. It's simply because Apple has kept education in mind while creating it. If you have an iPad, you might have also seen the Swift Playground app, which is also a great app to learn Swift and iOS.

22 Array Concepts Interview Questions Answers in Java

An array is one of the fundamental data structure and most of other advanced data structures like list, hash tables are built using arrays.  Good knowledge of fundamental data structures like the array, linked list, a binary tree is not just essential for writing better code but also doing well on Programming Job interviews. Array-based questions are quite popular on Java interviews. There are two types of question you will find, first which are based upon array implementation in Java and second which are based upon how to use an array data structure to solve some coding problems. The first type of question is quite popular in the telephonic round of Java interview and second is usually asked on written test and face-to-face interviews.

QuickSort Algorithm Example in Java using Recursion - Sorting Algorithm Implementation

The Quicksort algorithm is one of the very popular sorting algorithms in programming, often used to sort a large array of numbers. Though there is numerous algorithm available to sort a list of objects, including integer, string and floating point number, quicksort is best for general purpose. It's a divide and conquers algorithm, where we divide the given array with respect to a particular element, known as 'pivot' such that the lower partition of the array are less than the pivot and upper partition elements of the array are higher than the pivot. The Quicksort is also one of the best examples of recursion, a key programming technique to solve Algorithmic problems. This algorithm is naturally recursive because it sorts the large list by dividing into smaller sub-list and then applying the same algorithm on those.

Top 10 Algorithm books Every Programmer Should Read

Algorithms are language agnostic and any programmer worth their salt should be able to convert them to code in their programming language of choice. Unfortunately, I have come across several programmers who are REALLY good on programming languages like Java or Python like knows minor details of API and language intricacies but has very poor knowledge of fundamentals Algorithms and Data Structure. Just ask them to implement any popular sorting algorithms like quicksort or merge sort and they will fall apart. If you expect them to know more advanced and complex algorithms like String processing algorithms, graph algorithms, tree traversal or greedy algorithms, be ready to check on Interviews, otherwise, you might end up with some surprises.

How to convert ArrayList to HashMap or LinkedHashMap in Java 8 - Example Tutorial

One of the common task in Java is to convert a List of object e.g. List<T> into a Map e.g. Map<K, V>, where K is some property of the object and V is the actual object. For example, suppose you have a List<Order> and you want to convert it into a Map e.g. Map<OrderId, Order>, how do you that? Well, the simplest way to achieve this is iterating over List and add each element to the Map by extracting keys and using the actual element as an object. This is exactly many of us do it in pre-Java 8 world but JDK 8 has made it even simpler. In Java 8, you can get the stream from List and then collect all elements into a Map by using a Collector. The collect() method of Stream class and java.util.stream.Collectors class gives you ample choices to decide which property goes into the key and which object goes into the value.

10 Things Java Developer Should Know about Lambda Expression of Java 8

The Lambda expression is one of the most important features of Java 8 which has opened a whole new dimension of programming paradigm in Java. It is the feature which made the Functional Programming possible in Java because now you can pass the code to a function to execute as opposed to an object. You might be a bit surprised but if you look from a developer's point of view, it is nothing but a way to pass code to a method in Java. Technically, it's an expression where you can define parameters and then the code which uses those parameters, similar to a method in Java, but you don't need to write boilerplate code e.g. method name, return type, argument type etc. Most of those details are inferred by compiler and JVM from the context in which lambda expression is used.

How to Remove an Element from Array in Java with Example

There is no direct way to remove elements from an Array in Java. Though Array in Java objects, it doesn't provide any methods to add(), remove() or search an element in Array. This is the reason Collection classes like ArrayList and HashSet are very popular. Thanks to Apache Commons Utils, You can use there ArrayUtils class to remove an element from array more easily than by doing it yourself. One thing to remember is that Arrays are fixed size in Java, once you create an array you can not change their size, which means removing or deleting an item doesn't reduce the size of the array. This is, in fact, the main difference between Array and ArrayList in Java.

Top 5 Courses to learn Java 9, 10, and 11 in 2019 - Best of Lot

Hello guys, even though Java 12 is around the corner, many developers are still on Java 8 and not really caught up with changes on Java 9, 10 or 11. If you are also on the same boat and want to start with Java 9 features then you have come to the right place. In this article, I am going to share some of the best online courses to learn changes in Java 9, 10, 11. These JDK releases are packed with some powerful features e.g. modules, API enhancements e.g. factory methods for an immutable list, set, and map, some changes on stream API and optional class, new features on process API etc. Since it's always good to keep yourself up-to-date, its time to spend some time to learn those new features and make use of them to write better code in Java.

6 Data Structures Every Java Programmer Should Know

Java API provides built-in support for common data structures, essential for writing programs e.g. array, linked list, map, set, stack and queue. You don't need to implement these data structure by yourself, you can directly use it in your program, thanks to rich and efficient implementation provided by Java API. This is also one reason, why Java is the best programming language. Since data structure is core to any program and choice of a particular data structure greatly affects both functionality and performance of Java applications, it's worth an effort to explore different data structure available in Java.

Top 5 Free Angular Courses for Web Developers to Learn Online

Google's Angular is one of the most popular JavaScript frameworks for creating web apps. It helps you in creating complex web applications in less time. It's maintained by Google so you can also rest assured that this powerhouse of a framework is built with speed and purpose and here for a long run. The Angular Framework is also the most popular framework in the world for building single page applications.  The framework was first launched as Angular JS which allowed building a web application using Model View Controller concept and it was hugely popular but it was later re-written completely, which is now known as simply Angular or Angular 2.

10 Examples of Array in Java - Tutorial

Along with the String, the array is the most used data structure in Java. In fact, String is also backed by a character array in Java and other programming languages. It's very important for a Java programmer to have good knowledge of array and how to do common things with array e.g. initialization, searching, sorting, printing array in a meaningful way, comparing array, converting an array to String or ArrayList and doing some advanced slicing and dicing operation with an array in Java. Like my previous tutorials 10 examples of HashMap in Java, I'll show you some practical example of array in Java. If you think, any important operation is not included, you can suggest their examples and I'll add them to this list.

10 Technologies Programmers Should Learn in 2019

Hello Guys, we are just one week away from 2019 now and many of you might have already made your goals about what to learn in 2019, but if you haven't then you have come to the right place. In this article, I am sharing some of the best framework and libraries for web development, mobile app development, and big data, an application developer can learn in 2019. The New Year will be all about the mobile. machine learning, and next-generation web with a greater focus on big data technologies like Hadoop and Spark, but you can still learn the popular Java and Web development frameworks like React, Node.js, Spring Boot to take your career to next level. These frameworks are tried and tested and will be here for at least the next 5 years to come.

6 Free Maven and Jenkins Online Courses for Java Developers

Maven and Jenkins are two of the most popular tools in the Java world. Maven helps to organize your project and provide support to build and deploy Java projects while Jenkins can provide continuous integration and delivery by completely automating build and deploy projects. As a Java developer, it's very important that you know both Maven and Jenkins because every other company is using it and not knowing these technologies will only put you behind other candidates if you go for a job. If you have yet to learn Maven and Jenkins then you have come to the right place, In this article, I will tell you 6 free course you can take to learn Maven and Jenkins online, but before that, let's understand what is Maven and Jenkins and what are their purpose.

7 Examples of HttpURLConnection in Java - Sending GET and POST Request

The HttpURLConnection is an important class in java.net package which allows you to send an HTTP request from Java program. By using this you can send any kind of HTTP request e.g. GET, POST, PUT, DELETE, HEAD etc. It also provides several methods to configure your HTTP requests e.g. it allows you to add headers, add request parameters, attaching cookie, configuring timeout, handling redirects and so on. A good knowledge of this class is important for Java developers working on both core Java and Java web application.

21 String Programming and Coding Interview Questions With Solutions

In this article, I am going to share 21 of the most common String based Programming and Coding interview questions from Java developer interviews. These questions require you to write code to solve the problem and they are different from traditional Java String questions like how substring method works in Java or when to use the intern() method of String in Java? Since coding and problem solving is an important part of any programming job interview, it's imperative that you know how to solve them in time and on pressure situation, which comes only after doing practice with a right set of questions. Since these questions are already tried and tested and appeared in many interviews, they will provide you the experience you need to crack your coding interview.

Top 5 Free Bootstrap Course to Learn Online - Best of Lot

Bootstrap is one of the most popular front-end libraries which provides a customizable template of HTML, CSS, and JS for creating a modern and responsive website. All the nice website you see these days with large fonts and slick form fields are built using Bootstrap. If you want to learn Bootstrap and looking for some good online courses then you have come to the right place. In this article, I am going to share some of the awesome Bootstrap courses which are also free and you can use them to kick-start your journey with the Bootstrap framework. If you are interested in modern web development this is the framework you must learn this year.

10 Books for Coders of All levels - Must Read Best of Lot

Coding is one of the most important skills for programmers and if you want to survive as a programmer you must improve your coding skill. Gone are the days, when you can get a software development job without having you to write a single line of code and then somehow survives in the job by doing support, coordination, and other non-coding activities. Companies, both big and small are increasingly testing coding skills of candidates before hiring. It's very common for programmers to pass a coding test before a telephonic round of interview. Some of the companies even hire websites like HackerRank and others to check the coding skill of potential candidates, many others give candidates take home coding tests. In short, companies have a lot of focus on the coding skill of potential hires.

How to implement PreOrder traversal of Binary Tree in Java - Example Tutorial

The easiest way to implement the preOrder traversal of a binary tree in Java is by using recursion. The recursive solution is hardly 3 to 4 lines of code and exactly mimic the steps, but before that, let's revise some basics about a binary tree and preorder traversal. Unlike array and linked list which have just one way to traverse, I mean linearly, binary tree has several ways to traverse all nodes because of its hierarchical nature like level order, preorder, postorder and in order. Tree traversal algorithms are mainly divided into two categories, the depth-first algorithms, and breadth-first algorithms. In depth-first, you go deeper into a tree before visiting the sibling node, for example, you go deep following the left node before you come back and traverse the right node.

5 Free Database and SQL Query Courses for Programmers to Learn Online

Hello guys, I have been sharing some free programming resources e.g. books and courses in this blog for quite some time. Earlier I have shared free courses on Java, Maven, Spring, and Data Structure and Algorithms and today I'll share some of the free online training courses to learn SQL and Database. Why you should learn SQL? Well, it's one of the must-have skill for programmers, application developer, and IT professionals. Like Linux, this is one skill which is going to serve you longer than any other programming language, framework, or library. The SQL is used to interact with Database Systems like Oracle, MySQL, and Microsoft SQL Server. As per ANSI (American National Standards Institute), SQL stands for the Standard Query language for Relational Database Management Systems.

100+ Data Structure and Algorithm Interview Questions Answers for Programmers

Data structure and algorithms are core part of any Programming job interview. It doesn't matter whether you are a C++ developer, a Java developer or a Web developer working in JavaScript, Angular, React, or Query. As a computer science graduate, its expected from a programmer to have strong knowledge of both basic data structures e.g. array, linked list, binary tree, hash table, stack, queue and advanced data structures like the binary heap, trie, self-balanced tree, circular buffer etc. I have taken a lot of Java interviews for both junior and senior positions in the past, and I have been also involved in interviewing C++ developer. One difference which I have clearly noticed between a C++ and a Java developer is their understanding and command of Data structure and algorithms.

Top 5 Free React JS Courses for Web Developers to Learn Online

React JS or React is one of the most popular frameworks or Javascript library for building user interfaces. It's backed by Facebook and it's often viewed as an alternative to the great Angular framework by Google. React is also very flexible, fast, easy to learn and fun to work with. It is designed to make the process of building modular, reusable user interface components simple and intuitive and that's why most of the modern GUI and web applications are build using React framework. It is developed at Facebook and it focuses on the 'View' aspect of MVC in web applications. The component-based development is one of the biggest advantages of React library which is both rich and extensible.

Merge Sort in Java - Algorithm Example and Tutorial

The merge sort algorithm is a divide and conquers algorithm. In the divide and conquer paradigm, a problem is broken into smaller problems where each small problem still retains all the properties of the larger problem -- except its size. To solve the original problem, each piece is solved individually; then the pieces are merged back together. For example, imagine you have to sort an array of 200 elements using the bubble sort algorithm. Since selection sort takes O(n^2) time, it would take about 40,000-time units to sort the array. Now imagine splitting the array into ten equal pieces and sorting each piece individually still using selection sort. Now it would take 400-time units to sort each piece; for a grand total of 10*400 = 4000.

How to Rotate an Array to Left/Right by a Given Number in Java - Coding Problem

Hello guys, welcome to this post with another array based coding problem. In the last article, we've learned about finding missing numbers in the array with duplicates and today we'll solve the problem of rotating an array by left or right by a given number. For example, suppose an integer array {1, 2, 3} is given and it was asked to rate this array to the left by 3 then the result array will look like {2, 3, 1} because it was rotated twice on left. Similarly, if you are asked to rotate the same array twice by right then you'll get {1, 2, 3}, the same array is back. This is an interesting problem and it's quite easy to solve but I have seen many programmers struggle with this one as well. So, a little bit of practice and learning will not hurt.

Top 5 Free Courses to Learn Web Development in 2019 - Best of Lot

Hello guys, I have been sharing a lot of free online courses and books on various technology and programming language e.g, Python, Java, C++, JavaScript, PHPReact, Angular, Spring in this blog from quite some time and today I have brought some great free courses to learn the basics of web development. Web Development is an important skill for programmers in this era of Startups. As a programmer or software developer, you should know how to create a website and how to create a mobile app of your own. Though it's not easy. Coding is like art and many people born with coding sense, I mean they love coding, they love to create stuff like websites, mobile apps, games etc and they love to automate things.

5 Free Servlet, JSP, and JDBC Online Courses for Advanced Java Developers

If you are a Java developer working on a Java JEE projects like a Java Web application running on Tomcat or Glassfish, or you want to get into that by learning server-side technologies like Servlet, JSP, and JDBC then you have come to the right place. In this article, I will share some free online courses to learn Servlet, JSP, and JDBC at your own pace. If you want to become a rockstar Java web developer then you must have a good understanding of these basic web technologies before you learn frameworks like Spring and Hibernate. These frameworks work on top of these basic technologies and if you don't know them then you would often struggle to debug and troubleshoot problems in the real world.

5 Spring Framework Books for Java developers (Includes Spring Security and Spring Boot) - Best of lot

Spring framework is one of the most popular frameworks in the Java world which used to develop Java application, both core Java, and web application. It is also one of the most job oriented skill for Java developer, hence many beginners and intermediate Java programmers try to learn Spring framework by their own. Though there are some good Spring training courses available online, books are still the most popular and preferred way to learn Spring frameworks like Spring core, Spring Boot, Spring MVC, Spring Batch or Spring Security.  I often receive queries for Spring book recommendations e.g. which Spring book is good for beginners, or which Spring book is good for intermediate and advanced developers, which book should I read to learn Spring boot, Spring Cloud, Spring Batch or Spring security etc?

7 Common Socket Errors and Exception in Java Application [Solved]

In this blog, I plan to talk about some common exceptions and errors that arise while using sockets. Quite often, these socket issues arise out of application bugs, system settings or system load. It might be an unnecessary delay to go to product teams, only to discover that the issue can be resolved by tuning/configuring your local settings. Understanding these messages will not only help resolve the issues but also make a conscious effort in avoiding these scenarios while developing applications.

30+ Spring MVC Framework Interview Questions Answers for Java/JEE Developers

Spring Interview Questions Answers 
Spring Interview Question is one of the first things Java programmer should prepare before appearing on any Java or Spring interview. With the immense popularity of Spring frameworks like Spring MVC and Spring Boot in Java world, focus on Spring skills on interviews are increasing day by day. For those who don't know, the Spring framework is one of the most popular frameworks for Java applications, which aims to simplify Java development. It revolutionized the Java development when it initially came with concepts of  Dependency Injection and Inversion of Control, which made writing testable and maintainable Java application

5 Good Books to Learn Java 8 Functional Programming

Hello guys, if you are learning Java 8 features like lambda expressions, Stream API, and functional programming in Java and looking for some exciting books and resources then you have come to the right place. In the past, I have shared some of the best Java 8 tutorials and courses and today I'll share some of the best books you read to learn Java 8 better. I will not only tell you which books to read but also why read that particular book. I know that online courses are getting better and better every day and even I am using to learn new technologies like Spring 5 and Java 11 but books still have its place because they provide most in-depth coverage of any topics, which is needed to master the topic and become an expert.

How to Convert java.util.Date to java.time.LocalDate in Java 8 - Examples Tutorial

Hello guys, once you move to Java 8, you will often find yourself working between old and new Date and Time API, as not all the library and system you interact will be using Java 8. One of the common tasks which arise from this situation is converting old Date to new LocalDate and that's what you will learn in this tutorial. There seems to be a couple of ways to convert a java.util.Date to java.time.LocalDate in Java 8, but which one is the best way? We'll figure it out in this article, but first, let's explore these different ways to convert a java.util.Date object to LocalDate in Java 8 code.

7 Linux cURL command Examples - How to test RESTful Web Services using in UNIX

The curl or cURL command of Linux is a very powerful and versatile command which allows you to send sophisticated HTTP request right from your Linux command line window. You can use the cURL command to test your RESTful Web Services by sending GET and POST request, doing authentication, saving a cookie in the file etc. The curl command is, in fact, the go-to tool for many Java and Spring developers working in web application and consuming data from the secured RESTful Web Services, but you can also use it test your simple REST Web APIs without security. I have used it many times to check if our Web service is up or not, or is there any error while accessing those services.

Top 5 Amazon Web Services or AWS Courses to Learn Online - FREE and Best of Lot

Hello guys, if you are thinking about cloud, cloud-computing and looking at the various cloud providers like AWS, GCP, or Azure then you are going in the right direction. Future lies with Cloud and it's very important for every developer to learn about cloud computing solutions. When we talk about Cloud the first thing comes in mind is AWS, the biggest Cloud Computing platform and that's why I suggest a lot of developers learn it. If you want to learn Amazon Web Services, popularly known as AWS and looking for some awesome resources like books, courses, and tutorials then you have come to the right place. In this article, I am going to share some of the best Amazon Web Services or AWS online courses which will help you to learn this revolutionary and valuable technology free of cost.

Linux Crontab Command Example - How to backup and load Cron Jobs from a File in UNIX

If you have been using Linux for some time then you might know about cron jobs. They are the scheduler which can be used to automatically start processes in a Linux box. I have worked on many projects which used cron jobs to start the Java process and environment daily or weekly basis. They are similar to Autosys when it comes to scheduling job but cron is a Linux command as opposed to Autosys which is separate application altogether. In Linux, crontab command is used for scheduling and automating jobs or process. You can also use it for loading cron jobs from a file, listing existing cron entries, and editing them. It manages the cron table that is used by the cron daemon in Linux to execute the cron jobs.

5 Free BlockChain Online Courses for Programmers to Learn

Hello guys, how are you doing? hope you all are having a great time and working towards your goal this year. I have been sharing a lot of courses and tutorials in this blog about what to learn in 2019, starting from tools to frameworks, from libraries to programming languages, but one of the most important technology, you can learn in 2019 is the Blockchain technology. It's one of most talked about technology at the moment and considered to be the next big thing after the invention of the internet as they provide a way to attain digital trust on the Internet.

Linux mailx + mutt command Examples - 4 ways to send Email with Attachment from RHEL 5 and 6 Server

One of the common task for programmers working in Linux machine is to send emails, for example, your Java applications are running on Linux like RHEL 5 or RHEL 6 version and you need to send a report of all the clients connecting to your application. An easy way to accomplish this is to write a shell script, which will dump all clients in the log file and then use grep command and generate a report. If you have to grep logs from multiple hosts, you can also use the SSH command to run the same command on multiple hosts. Once you have got the list of clients connecting to your application, you can just send the CSV file to yourself in an email or to your application DL, or a group of users you want to.

Top 10 Data Science and Machine Learning Certification Courses to Learn Online - Best of Lot

If you work in the technology field today like you are a programmer or software engineer then I am sure you have heard about terms like Data Science, Machine Learning, Deep Learning, Artificial Intelligence etc. They are the latest technologies which are impacting every single sector just like IT does it when it comes the first time. It doesn't matter if you are working for a bank or insurance sector, airspace or defense, all fields were impacted by IT and in near future, they will be impacted by machine learning and artificial intelligence. If you are wondering, let me give you a brief overview. Machine learning is all about training machines to do the job which was only possible by humans before, for example seeing a photo and recognizing what is the object like a car, a human or a cucumber.

How to set JAVA_HOME and PATH in Linux - Step by Step Guide

Hello guys, welcome to the world of Java application programming. One of the hardest thing to mater is not any feature but environment-specific details which nobody teaches. To bridge that gap, I am going to cover a couple of very important environment variables like PATH and JAVA_HOME.  The JAVA_HOME environment variable points to the JDK installation directory and used by many Java tools and applications like TomcatMaven, Eclipse, NetBeans or IntelliJIDEA etc. to figure out Java executables as they need Java for running. Like in the previous article I explained about a Maven issue (invalid target release: 1.7, 1.8)  related to Java version which occurred even though the correct version of Java installed on the machine but JAVA_HOME was pointing to an older version.

5 Free Courses to learn Machine Learning and Deep Learning in 2019

Hello guys, Happy New year 2019. We are already in the second week of January and I am sure you all have made your goals and may be looking for the ways and resources to achieve them. If one of your goals is to learn Machine learning and Deep learning in 2019 then you have come to the right place. In this course, I am going to share some of the best free courses to learn Machine learning and Deep learning online. Btw, If you are thinking to learn Data Science, Machine learning, or Deep learning than you are not alone, more and more people are starting with these advanced skills around the world.

Top 10 SQL and UNIX Interview Questions for Programmers

The SQL and UNIX are two of the most essential skills for any programmer. It doesn't matter whether you are applying for the job as Java developer or C++ developer, Python developer or Ruby programmer, SQL and UNIX always have some role to play in your job. It's even important for people who have less to do with programming like application support guys, business analysts, project managers, and subject matter experts.  Hence, it's imperative for any programmer or IT professional to prepare both SQL and UNIX well before going for any job interview. This becomes even more important if you are going for a support engineer role, rather for a development role because than the importance of SQL, Database, and Linux skill increases as compared to programming language you know.

Top 10 Free Algorithms and Data Structure Courses for Programmers

Algorithms and Data Structure are two of the most fundamentals and important topics from Computer Science which is used everywhere in software development. I strongly believe that a good knowledge of these two topics are also key to become a better programmer because a person who has a good understanding of algorithms and data structures can make thoughtful choices and write programs which can handle changes better and perform well. They are also important to crack coding interviews at top tech companies like Google, Microsoft, Amazon, Facebook, and Apple, which puts a lot of emphasis on candidate's ability to use existing data structure and algorithms to solve complex problems they have never seen before.

GREP Command Example in Linux - How to Search All Files Matching Specific Text

One of the most common task while working in programming projects is finding files containing some specific text e.g. you have your application deployed in Linux server and you are migrating your database from one server to another. Now, you want to file all config files and scripts which are referencing your old database using the hostname or IP address, so that you can replace them with an alias. Well, you should always use an alias to connect to the database or any other system, but sometimes it happens you have to use hostname. Anyway, how do you find all those files containing hostname in your Linux machine? Well, the grep command is here to help you.

3 Books and Courses to Learn RESTful Web Services using Spring and Java

Hello guys, if you know Spring framework then there is a good chance that you have heard about the classic Spring in Action book by Craig Walls. It's one of the best books to learn Spring and many Java developers, including me, has learned Spring from that. But, even though the Spring in Action 5th Edition is one of the best books to learn Spring framework, it's just not enough to learn intricacies of developing a modern, full-featured RESTful Web Service using Spring Framework. It does have a chapter on developing RESTful Web Services and nicely explains concepts like @RestController, @ResponseBody, @ResponseStatus, HTTP message converters, content negotiation but that barely touch the surface of developing a production quality RESTFul Web Service.

find + du command example Linux - How to search/print large files and directories with size to free disk space?

One of the common problem while working in Linux is to find large files to free some space. Suppose, your file system is full and you are receiving an alert to remove spaces or if your host is run out of space and your server is not starting up, the first thing you do is find top 10 largest files and see if you can delete them. Usually, old files, large Java heap dumps are good candidates for removal and freeing up some space. If you are running Java application e.g. core Java-based programs or web application running on Tomcat then you can remove those heap dump files and free some space, but the big question is how do you find those? How do you know the size of the biggest file in your file system, especially if you don't know which directory it is? We'll try to find answers for some of those questions in this article.

5 Free Object-Oriented Programming Online Courses for Programmers

The OOP or Object Oriented Programming is a paradigm which allows you to write a program by modeling real-world things in terms of class and object. It not only make to represent a real-world thing in the programming world easier but also allow you to manage the complexity of your program. Even though there are several programming paradigms e.g. procedural and functional, most of the code we write today is object-oriented and some of the most of popular programming languages are object-oriented e.g. Java, Python, PHP, and JavaScript all supported object-oriented programming.

How to Compare String by their length in Java?

One of the common programming tasks is to compare String, sometimes by their value and sometimes by their length. The natural way to compare String is the lexicographic way, which is implemented in the compareTo() method of String class, but sometimes you need to compare String by their length. You cannot use the default compareTo() method for that task, you need to write your own custom Comparator, which can compare String by length. Don't worry, It's easy to compare multiple String by their length, all you need to do is write a Comparator implementation which calculates their length using the length() method and compares them.

Top 10 Free Java Courses for Beginners and Experienced Programmers

The Internet is full of useful resources and no matter what you want to learn there is something useful available for free. You just need to commit your time and effort. But at the same time, it's difficult to choose in the huge sea of free tutorials and courses on the internet. If you are not careful, you will spend most of your time browsing and changing courses without learning anything. That's where a curated list helps. Curation is my hobby and passion. I love to read books and courses which allows me to curate useful resources and share with you guys.

Map Reduce Example in Java 8

The map-reduce concept is one of the powerful concepts in computer programming, particularly on functional programming which utilizes the power of distributed and parallel processing to solve a big and heavy problem in quick time. From Java 8 onwards, Java also got this powerful feature from the functional programming world. Many of the services provided on the internet like Google Search are based on the concept of the map and reduce. In map reduce a job is usually split from the input data-set into independent chunks which are processed by the map tasks in a completely parallel manner. The framework then sorts the outputs of the map operation, which are then supplied to the reduce tasks.

5 Free Docker Courses for Java and DevOps Engineers

If you are an application developer working in Java or C# or any other language and wants to become a DevOps engineer or someone who wants to learn Docker then you have come to the right place. In this article, I am going to share some of the free Docker courses you can use take online to learn Docker by yourself. These courses are great for both beginners and intermediate developers who have basic ideas about Docker. If you don't know what is a Docker and how it works then let me give you a brief introduction. Before starting just look at the Docker's logo which is a whale carrying containers, does that strike something? Well, if you add this image with the name Docker you might think about shipping companies, which carry containers from one part of the world to another.

Top 10 Open Source Frameworks and Libraries Java Web Developers Can Learn in 2019

Java programming language and Platform has been very lucky in terms of frameworks, standards, and libraries, I guess which is one of the important reason for its huge success. Apart from standard frameworks like Swing for desktop GUI application, JavaFX, Servlets and JSP, EJB, and JSF, there are a lot more open source framework and libraries available for Java programmers. These Open source framework, not only helps and speed up development but also enforce to use best practices required to build enterprise Java application and desktop application. Frameworks like Spring, which in my opinion gives a much-needed boost to the Java platform, enforces dependency Injection design principle at the core, which is key to build a loosely coupled system.

Top 5 Spring Security Online Training Courses for Java Developers

Security is one of the most important aspects of a modern web application, be it a Java web application, .NET or writing using any other web technology. In the Java world, Spring Security rule the security space. It's one of the rare frameworks which provided many security features e.g. authentication, authorization, session management, remember me and several other useful features out-of-the-box. Since there was no competition to Spring security and it does its job very well, it soon becomes the de-facto standard for implementing security in both Java web applications, REST APIs and core Java applications. The rise of the Spring framework certainly helps it to cement its place as well.

How to Convert String to LocalDateTime in Java 8 - Example Tutorial

Hello guys, today, I will talk about a common problem while working in a Java application, yes you guessed it right, I am talking about String to Date conversion in Java. I have discussed this before (see the Date to String) when Java 8 was not out but with Java 8, I don't see any reason to use old date and time API and hence I am writing this post to teach you how to convert String to Date in Java 8 or beyond. Suppose you have a date time String "2016-03-04: 11:01:20" and you want to convert this into a LocalDateTime object of Java 8 new date and time API, how do you do that? Well, if you have worked previously with String and Date then you know that you can parse String to Date in Java.

Can you add a non-abstract method on an interface in Java?

Well, prior to Java 8, it wasn't possible to add non-abstract methods in Java but nowadays you can add non-abstract static, default, and private methods in Java interface. The static and default methods were supported as part of interface evolution in Java 8 and you can add private methods on an interface from Java 9 onwards. Since long, many Java programmers feel that there is no real use of an interface, well that's completely wrong, given how interface allows you to write generic, decoupled code, most of those sentiments comes from no implementation on the interface.

Difference between include directive, include action and JSTL import tag in JSP?

There are three main ways to include the content of one JSP into another:

include directive

JSP include action

and JSTL import tag

The include directive provides static inclusion. It ads content of the resource specified by its file attribute, which could be HTML, JSP or any other resource at translation time.

Any change you make in the file to be included after JSP is translated will not be picked up by include directive.

10 Examples to Format and Parse Date Time in Java 8 using LocalDateTime and DateTimeFormatter

Parsing and formatting dates are other important topics while working with date and time in Java. Even though old Date API had SimpleDateFormat and DateFormate class to support formatting of date and parsing texts, they were not simple, or should I say there were just simple in writing bad code. You might know that SimpleDateFormat was not thread-safe and quite heavy to be used as a local variable. Thankfully, this has been sorted now with new LocalDateTime class and DateTimeFormatter class, which has several inbuilt formatter e.g. BASIC_ISO_DATE format which prints dates in yyyyMMdd format e.g. 20160616 and ISO_DATE which prints date as yyyy-MM-dd e.g. 2016-06-16. It has several useful formats to represent popular date formats around the world e.g. the date format used in the USA is different than date format used in UK and India.

How to Convert Stream to ArrayList in Java 8 - Collectors.toCollection() Example, Tutorial

You can use Collectors.toList(), toSet() and toMap() to get all elements of Stream into any Collection e.g. List, Set or Map, but if you want to get a particular collection e.g. ArrayList, then you need to use Collectors.toCollection(ArrayList::new) method. This method first creates an ArrayList using method reference and then adds all elements of Stream into the ArrayList. It's very useful if you have a long list of String and you want to create a smaller list containing only String starting with the letter "b" e.g. "Bluehost". All you need to do is first get the stream from List by calling stream() method, then call the filter() method to create a new Stream of filtered values and finally call the Collectors.toCollection(ArrayList::new) to collect those elements into an ArrayList.

Top 5 Free Big Data Courses to learn Hadoop, Spark Online - Best of Lot

If you want to learn Big Data technologies in 2019 like Hadoop, Apache Spark, and Apache Kafka and you are looking for some free resources e.g. books, courses, and tutorials then you have come to the right place. In this article, I am going to share some of the best free online courses to learn Hadoop and Spark from Udemy and Pluarlsight at your own pace. I personally like to start with FREE resources before I have enough knowledge to choose the right book or enroll in a little expensive course. It's also my passion to surf web to find great free resources and share with you guys.

3 Examples to Loop Through a List in Java 8

3 ways to Loop through a List in Java
There are multiple ways to traverse or loop through a List in Java e.g. by using an Iterator, by using an enhanced for loop of Java 5, and not the forEach() method of Java 8. Given a List is an index based collection if you know the index you can retrieve an object from List and because of this, you can also use traditional for loop which keeps count for iterating List. Now the question is whether should you use the Iterator or enhanced for loop, or the forEach() method of Java 8 for looping over List in Java. Well, it depends on what you are doing with the object, if you need to remove some objects from List than iterating using Iterator is best choice to avoid ConcurrentModificationExceptionbut if you are not removing any element and just doing some operation with each element than enhanced for loop is much cleaner ways to do that. 

5 Free HTML and CSS Courses to Learn Front End Web Development Online

HTML and CSS are two pillars of web development, they are used to create web pages you see every day. HTML provides the structure to your web page and CSS provides them the style to look better. If you want to become a front-end web developer or web designer then a good knowledge of HTML and CSS is a must. Even though modern day web development is all about framework and library e.g. Angular and React, you still need to know HTML and CSS to understand what's going on and troubleshoot any issue you face while developing a web application. Btw, JavaScript is another pillar of web development but we'll not discuss this article. I have already shared some good books and courses to learn JavaScript before

How to Remove Objects or Elements while Iterating over ArrayList in Java - The Right way

One of the common problems many Java Programmers face is to remove elements while iterating over ArrayList in Java because the intuitive solution doesn't work e.g. you just cannot go through an ArrayList using a for loop and remove an element depending upon some condition. Even though java.util.ArrayList provides remove() methods e.g. remove (int index) and remove (Object element), you cannot use them to remove elements while iterating over ArrayList in Java because they will throw ConcurrentModificationException if called during iteration. The right way to remove objects from ArrayList while iterating over it is by using the Iterator's remove() method.

What is double colon (::) operator in Java 8 - Example

The double colon (::) operator is known as the method reference in Java 8. Method references are expressions which have the same treatment as a lambda expression, but instead of providing a lambda body, they refer to an existing method by name. For example, to print all elements of the list you can use the forEach() method as follows

list.stream.forEach( s-> System.out.println(s));

but here you can replace lambda expression with method reference to improve readability as shown below:

list.stream.forEach( System.out::println);

You can use method reference or double colon operator to refer a static method, an instance method, or a constructor.

5 Free Oracle and Microsoft SQL Server Online Courses

If you are an application developer e.g. someone developing a server-side application using Java or .NET or any other programming language which uses a database like Oracle and Microsoft SQL Server or a junior DBA then you must learn these database technologies to effectively work in your Job. Even though your organization might have DBAs or Database Administrators to help you with the database, more often than not, it's application developers who end up writing SQL scripts to create data, upload data, query data, and writing complex stored procedures and triggers to implement application functionalities. DBAs job mostly does database installation, access control, security, and other database admin stuff.

5 Best Courses to Learn Spring Boot in Depth

Hello guys, if you remember, one of my goals was to learn Spring Boot in 2019 and I have started working towards it. As I have talked about my 3 point action plan to learn a new technology, the first step is to attend some online courses and start building from that. If you are not sure what is Spring Boot and why should you learn Spring Boot then let me tell you that it should be the first Java framework you should learn in 2019. The Spring Boot makes it really easy to work with Spring framework by removing all the starting hurdles with respect to setup and configuration. In one word, it makes it possible to write Spring-based Java application and run them like core Java application e.g. from the main method.

Default Methods, Multiple Inheritance and Diamond Problem in Java 8

Ever since Java 8 introduced default and static methods in JDK 8, it's become possible to define non-abstract methods in interfaces. Since in Java, one class can implement multiple interfaces and because there can be concrete methods in interfaces, the diamond problem has surfaced again. What will happen if two interface has methods o the same name and a Java class inherit from it? Many Java programmer also asks me the question that, is Java 8 is also supporting multiple inheritances of classes? Well, it's not but the doubt is genuine because interface with methods is similar to abstract class or in that any Class in Java.

5 Free Apache Spark Course for Java, Scala, and Python Programmers to learn Online

Hello guys, if you are thinking to learn Apache Spark to start your Big Data journey and looking for some awesome free resources e.g. books, tutorials, and courses then you have come to the right place. In this article, I am going to share some of the best, free online Apache Spark courses for Java, Scala, and Python developers. If you don't know what is Apache Spark? and Why it's so important in the Big Data world then let me give you a brief overview first. Apache Spark is another cluster computing framework like Hadoop which is used to analyze a huge data set, but it's much faster as compared to Hadoop which makes it ideal for today's high computing needs e.g. processing huge amount of data.

How to Convert Stream to Array and ArrayList in Java 8 - Tutorial Example

It's relatively easy to convert a Stream to an array in Java 8 by using the toArray() method of java.util.Stream class. By using this method you can convert any type of Stream to a corresponding array like a Stream of Strings can be converted into an array of String, or a Stream of integers can be converted into an array of Integers. The Stream.toArray() method is also overloaded, the one which doesn't take any parameter returns an Object[] which might not be very useful, particularly if you want to convert Stream of T to array of T. On the other hand, the overloaded version of toArray(IntFunction[] generator) returns an array containing the elements of this stream, using the provided generator function to allocate the returned array, as well as any additional arrays that might be required for a partitioned execution or for resizing.

Top 5 Free jQuery Online Training Courses for Web Developers - Best of Lot

Hello guys, if you are thinking to learn jQuery and looking for some awesome free resources e.g. books, tutorials, and online courses then you have come to the right place. In this article, I am going to share some of the best free jQuery courses from Udemy and Pluarlsight which you can take to learn this awesome JavaScript library. In the past, I have also shared some free books and tutorials on jQuery, which complements these courses. You can also take a look at then while learning different parts of jQuery.  Before I share these free courses, let me brief you about what jQuery is and why you should learn it? Well, jQuery is a JavaScript library but unlike any other library it is very powerful and makes the client side scripting really easy.

Java 8 StringJoiner Example - How to join multiple Strings with delimiter in Java

While everyone was looking at the lambda expression and Stream API, JDK quietly sneaked some of the exciting methods on its API. There are a lot of hidden gems on JDK 8 and I have uncovered many of them already in this blog and today we'll talk about one of such gems which you can use in your day to day programming activities like joining much String together. The Java 8 has added a new class called StringJoiner to join Strings. The java.util.StringJoiner can be used to join any number of arbitrary String, a list of String, or an array of String in Java. You can choose any delimiter to join String like comma, pipe, colon or semi-colon. This class also allow you to specify a prefix and suffix while joining two or more String in Java.

Top 5 Free R Programming Courses for Data Scientists and ML Programmers

More and more people are learning R programming language to become a Data Scientist, one of the hottest and high paying technical jobs on the planet. Though, I am from Python camp when it comes on choosing between Python and R for Data Science, Machine Learning, and Artificial Intelligence, mainly because of the awesome libraries Python offers, I had tried R for a short time. If you are also on the same boat and want to try or learn R programming for Data Science and machine learning purpose and looking for some awesome free courses to start your journey then you can take some ideas from this article.

How to debug Java 8 Stream Pipeline - peek() method Example Tutorial

I have been writing about some important methods from Java SE 8  like map(), flatMap(), collect() etc from quite some time and today I'll share my experience about another useful method peek() from java.utill.stream.Stream class. The peek() method of Stream class can be very useful to debug and understand streams in Java 8. You can use the peek() method to see the elements as they flow from one step to another like when you use the filter() method for filtering, you can actually see how filtering is working e.g. lazy evaluation as well as which elements are filtered. the peek() method returns a stream consisting of the elements of this stream and performs the action requested by the client.