Friday, November 30, 2018

Top 5 Websites to Learn Coding in Java Online for FREE - Best of lot

Begin an author of a Java blog, I often receive questions like how to improve my coding skills?,  or how do I learn to code in Java?, or I am having difficulty solving programming problems, please help etc. This is mostly from programmers, who has just started programming or a graduate with programming degree or even some programmers with a year or two in Job. Like many other things in the world, to improve coding you need to code, code, and code - and to improve programming you need to write a program, and that's where many of these programmers fail. In 90% cases, they simply don't write enough program to develop programming logic and code sense and if without too much experience at data structures and algorithms, if they attempt problems given on sites like TopCoder, or Project Euler, they fail miserably.

Top 5 Free Git Courses for Programmers to Learn Online - Best of Lot

One of my goals in 2018 is to learn and master Git and I have been searching some good tutorials and courses to start with. The Internet is full of git tutorials and a simple Google search will leave you thousands of tutorials but the big question mark is where do you start? It's easy to pick a tutorial or a blog post if you have some background about what is Git, what it does? and how to use it but if you don't have much background then you need a course which can tell you all the information from the ground up. I personally like learning from a book or an online course before moving to blog posts as they were often well structured. When you search for Git courses in popular online course websites e.g. Udemy, Pluralsight or Coursera, you will find some good courses e.g. Git Complete: The Definitive Guide on Udemy and Git Fundamentals from Pluralsight which will teach you everything about Git step by step. These are excellent resources to start with Git.

Thursday, November 29, 2018

Spring Framework Certification FAQ - Frequently asked Questions Answers for Java Developers

If you are a Java developer, working in Spring framework and thinking to become a certified Spring professional but couldn't to do it in the past due to expensive mandatory training provided by Pivotal and its partners then there is a good news for you. From 10th May 2017, Pivotal made the Spring Core training optional for appearing to Spring certification exam, which means, now, it's not mandatory to take Spring training for Spring certifications (see here). Similar to Oracle's Java certifications, you can become a Pivotal certified Spring Professional by just buying the exam vouchers and scheduling your exam online using examlocal.com from anywhere in the world.

Wednesday, November 28, 2018

Top 5 books to learn Agile and Scrum for Programmers - Best of lot, Must Read

When I started my career, it was all waterfall model. You try, fail, and then with every version you get an improved version of a software. I pretty much used to this model of software development until I was introduced to Agile development methodologies in my next company. I was confused about Agile as some people say its Scrum and Sprint, other ways its XP and Kanban etc. The confusion lasted for a long time because I was afraid of asking questions (afraid of being perceived as dumb and someone who wastes time on meetings) and only getting information in bits and pieces and I wasn't good at searching books at that time. From that experience, I learned that, when you have confusion and want to learn more about a new technology, nothing is better than a book or online training courses to start with.

Tuesday, November 27, 2018

How to Check/Uncheck CheckBoxes in a Page using jQuery? Example Tutorial

In the last couple of articles, I have shared a couple of useful jQuery tips like reloading web page and working with tag selectors. Today, I'll show you how to check or uncheck a particular checkbox using jQuery, one of the most popular JavaScript framework. jQuery provides CSS like selectors which can make this kind of task trivial. If you remember, in HTML a checkbox is checked if the "checked" attribute is present and its value is not false, otherwise, it's unchecked. By using jQuery function prop() you can dynamically add this attribute or if present we can change its value i.e. checked=true to make the checkbox checked and checked=false to mark the checkbox unchecked.

Monday, November 26, 2018

How to delete a key value pair from a HashMap during Iteration in Java - Example tutorial

Suppose you have a Map or Dictionaries like HashMap or Hashtable, which contains key-value pairs like books and their prices, and you want to delete all books whose prices are greater than 40 USD, how do you that in Java? This is one of the most common scenarios while developing Java application and many Java programmer, will say that they will iterate over Map and check each entry and then use the remove(Object key) or remove(Object key, Object value) methods from java.util.Map to delete any mapping where the value is greater than 40 USD. Though the approach is right, the answer is wrong.

Sunday, November 25, 2018

How Http Basic Authentication works in Spring Security?

In the last article, you have learned how to enable Http basic authentication in Spring security based Java application and now we'll go one step further to understand how exactly http basic authentication works in Spring security. If you remember, when you use HTTP Basic for authentication purpose the client e.g. browser or a rest client sends login credentials in http request header. The header is aptly named as "Authorization" and it contains based 64 encoded string which is created by concatenating username and password using a colon. For example, if the username is "johnsmith" and password is "JOHN3214" then they will be concatenated as "johnsmith:JOHN3214" before encoded using base 64 encoding algorithms.

Wednesday, November 21, 2018

How to avoid deadlock in Java Threads?

How to avoid deadlock in Java? is one of the popular Java interview question and flavor of the season for multi-threading, asked mostly at a senior level with lots of follow up questions. Even though question looks very basic but most of the Java developers get stuck once you start going deep.

Interview questions start with "What is a deadlock?"
The answer is simple when two or more threads are waiting for each other to release the resource they need (lock) and get stuck for infinite time, the situation is called deadlock. It will only happen in case of multitasking or multi-threading.

Tuesday, November 20, 2018

How to convert float to long or int data type in Java?

Yesterday one of the new joiner Java Trainee Engineer from our team came to me and asked about how do you I convert a float variable into long or int data type? He was storing some values coming from another system in the database and only wanted to store value before the decimal point e.g. he was getting "3.144" and he wants to convert it to "3" to store into database. The good thing was that API was returning a float primitive value and you don't need to convert a String to float etc. I asked him whether he needs routing or not, which he wasn't sure but it turns out that he didn't need that. I explained to him how to do that and that's what you will find in this article as well. In short, there are 3 ways to convert a float value into long or int in Java, but we will only focus on long data type part.

Top 15 Java Multithreading, Concurrency Interview Questions Answers asked in Investment banks

Multi-threading and concurrency questions are an essential part of any Java interview. If you are going for any Java interview on any Investment bank e.g. Barclays, Citibank, Morgan Stanley etc for Cash Equities Front Office Java Developer position, you can expect a lot of multi-threading interview questions on your way. Multi-threading and concurrency are favorite topics on Investment banking interviews,  especially on electronic trading development jobs and they grill candidate on many tricky java thread interview questions. They just want to ensure that the guy has solid knowledge of multi-threading and concurrent programming in Java because most of them are in the business of performance which provides them a competitive advantage and it's hard to write correct and robust concurrent code.

Sunday, November 18, 2018

The @SpringBootApplication Annotation Example in Java + Spring Boot

Hello guys, today, we'll learn about the @SpringBootApplication annotation, one of the most important annotations from popular Spring Boot framework, which has changed the way Java developers use Spring framework for writing Java applications. In this article, I'll explain you the meaning of @SpringBootApplication and it's used in a simple Spring Boot application. We use @SpringBootApplication annotation on our Application or Main class to enable a host of features e.g. Java-based Spring configuration, component scanning, and in particular for enabling Spring Boot's auto-configuration feature.

Saturday, November 17, 2018

How to Schedule Spring Professional Certification Exam using Voucher Online - Step by Step Guide

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 Spring certification 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.

Friday, November 16, 2018

Do you Need to Pass OCAJP before taking OCPJP - Java Certification for SE 8 (1Z0-808 and 1Z0-809)

Even though we are now waiting for Java 11, the latest Java certification you can do is 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 on 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 than 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.

Thursday, November 15, 2018

Top 10 ConcurrentHashMap Questions from Java Interviews

The ConcurrentHashMap class part of concurrent collections package added on JDK 1.5 which contains utility classes like BlockingQueue, CopyOnWriteArrayList, CopyOnWriteArraySet etc. It is a replacement of synchronized hash-based map implementations e.g. Hashtable and synchronized HashMap. It implements Map and ConcurrentMap (a sub-interface of Map) interface which allows you to store key-value pairs. The class is similar to HashMap or Hashtable but it's more scalable and the right fit for concurrent Java application. Unlike Hashtable which achieves its thread-safety by compromising the scalability, ConcurrentHashMap uses advanced techniques e.g. dividing the map into segments to remain thread-safe and scalable at the same time.

Tuesday, November 13, 2018

Top 5 Soft Skill and Career Development books and Courses for Programmers

Most of the software developers, programmers, and coders spend a considerable amount of their time and energy on learning technologies which get obsolete in few years e.g. a new framework or a new programming language but they neglect something more important e.g. soft skills. Unlike technical stuff, soft skills will not only serve you good in your job and career but also in your life and it won't get obsolete as quickly as the new web application development framework you have just learned. Similarly, most of us put a lot of effort to get a job but after that, we don't put much effort to grow on that job, the result is many programmers and software developer stuck in their career.

Monday, November 12, 2018

5 Must Read Books to become Software Architect or Solution Architect

I receive a lot of queries from senior Java developers, who aspire to become software architect or solution architect e.g. what can they do to become a software architect? Which books, resources, or certifications can help? and general queries like how much experience you need to become software architect etc. In the past, I have been suggesting them individually about some books to read to expand their knowledge base and look at the software from architecture and design perspective and this article is a compilation of many of such suggestions. Since a lot of books can confuse, I have only select 5 best and must-read books from software architect perspective.

Friday, November 9, 2018

Top 5 RESTful Web Services with Spring and Java Courses for Experienced Developers

In the last article, I have shared some courses to learn Microservice development with Spring framework and today, I'll talk about RESTful web service developments. The REST API and RESTful Web Services needs no introduction, it's everywhere now and driving a new internet revolution. Most of the software development in the web space now also involves REST APIs. Gone are the days where the only interface for a web application was the browser, now most of them support REST APIs, which allows them to be accessible on any device e.g. mobile devices, tablets, apple watch and any other digital gadgets. It doesn't matter whether you are working for software giants like Amazon, Facebook or Google or working with startups like Uber or Netflix, REST APIs are everywhere.

Thursday, November 8, 2018

3 Ways to convert String to Boolean in Java? Examples

You can convert a String object to Boolean object or boolean primitive by using the Boolean.valueOf() and Boolean.parseBoolean() method. The steps are similar rot converting to String to other data types e.g. String to Integer and String to Long. You can use valueOf() method to convert String to Boolean object and parseBoolean() method to convert given String to boolean primitive value. Internally, valueOf() also uses parseBoolean() for parsing String but on top of that it also provides caching e.g. it can return Boolean.TRUE and Boolean.FALSE cached value for "true" and "false" string.  In fact, the Boolean.TRUE is returned only when String is equal to true ignoring case e.g. "True", "true", "TRUE" will evaluate into boolean true, hence Boolean.TRUE will be returned. For string like "Yes", Boolean.FALSE will be returned. We'll discuss the rules of String to boolean conversion in next section.

Sunday, November 4, 2018

How to Remove Leading/Trailing White Space from a String in SQL Server? LTRIM, RTRIM Example

Unlike Java, Microsoft SQL Server 2008, 2012, 2014,  and even the latest version don't have a built-in trim() function, which can remove both leading and trailing space from the given String. But, SQL Server does have two built-in functions LTRIM() and RTRIM() to remove leading and trailing space. The LTRIM() function removes space from the left side of String so you can use it to get rid of leading space, while RTRIM() removes white-space from the right side of String so you can use it to delete trailing space. You can even combine these two methods to create your own TRIM() method in SQL SERVER e.g. LTRIM(RTRIM(column)) will act as a TRIM() method because it removes both leading and trailing space.

Saturday, November 3, 2018

The best Course to Learn Spring Security 5 for Experienced Java Developers

If you are a Java Spring developer and working with Spring Security then you may be familiar with the "Learn Spring Security" course by Eugen Paraschiv of Baeldung.com. It is one of the most advanced and comprehensive courses on Spring Security and the best part of this course is that Eugen always keeps it up-to-date with new Spring Security release. Now that version Spring Security 5 is out - he has updated his course to use new features of Spring Security 5. Btw, there is some really cool new functionality coming in Spring Security 5 for the reactive programming model, and many other improvements and new features. But, the most important one is the release of OAuth2.

Friday, November 2, 2018

Top 5 Node.js and Express JS online courses for Web Developers

There is no doubt that JavaScript is the #1 Programming language in the world and Node.js is one of the biggest reason for that. Initially, JavaScript was considered just a client-side scripting language but Node.js has changed all that by allowing developers to create dynamic web pages on the server side using JavaScript. It is also rated as the most popular framework of 2017 on StackOverflow Developers survey. The most important benefit of Node.js is that it allows you to build a full stack application based on just one language, JavaScript. This is especially useful for start-ups which put a lot of emphasis on being able to iterate early and often.

Thursday, November 1, 2018

Top 5 Free Agile Courses for Programmers and Software Engineers - Best of Lot

Technology is changing at a rapid pace and market conditions, tough competition, and time-to-market are some of the biggest concerns for today's organizations, especially for technology companies. In order to adapt this fast-changing environment, most of the companies are now using the Agile model of development, testing, and project management. This enables the organizations to efficiently cope with changes and deliver faster and that's why for a programmer or an IT professional, a solid knowledge of Agile methodologies and framework is important. It doesn't matter whether you know the Waterfall model of development or not but it does matter whether you have worked in an Agile environment or not. In order to educate programmers about Agile, I have shared some of the books to learn Agile in past and today I am going to share some of the free online Agile courses you can take to learn Agile methodologies at your own pace.