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Top 5 Free Core Spring, Spring MVC, and Spring Boot Courses for Beginners to learn Online

I have been sharing a lot of resources e.g. books and courses recently and when I published my list of Top 5 courses to learn Spring and Hibernate, many of my readers asked about a similar list of free courses to learn Spring Framework like Core Spring, Spring MVC, Spring Security, and Spring Boot. That request was always back in my mind but I couldn't get time to put together a list, which I can share with you guys, but today is the day. In this list, I have compiled some of the best online free courses to learn Spring Framework from scratch, online at your own pace. You can not only learn core Spring like the framework which provides dependency injection, but also Spring MVC, the most important framework for a Java Web Developer, Spring Security, and Spring Boot to take your career to next level.

A Simple Example to Check if File is Empty in Java

One of the readers of my blog Javarevisited emailed me yesterday about how to check if a file is empty in Java and that's why I am writing this post to show that using an example. The common approach for checking if a file is empty or not is to first check if the file exists or not and then check if it contains any content, but Java has done that hard work for you. Well, it's pretty easy to check emptiness for a file in Java by using the length() method of the java.io.File class. This method returns zero if the file is empty, but the good thing is it also returns zero if the file doesn't exist. This means you don't need to check if the file exists or not.

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, like authentication, authorization, session management, remember me, and several other useful features out-of-the-box. Since there was no competition for 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.

Top 25 Examples of ConcurrentHashMap in Java [Tutorial]

The java.util.ConcurrentHashMap is one of the most important classes of JDK. It was introduced in JDK 1.5 along with other concurrent collection classes like CopyOnWriteArrayList and BlockingQueue. Ever since then, it has been a workhorse in concurrent Java applications. It won't be an exaggeration If I say there is hardly any concurrent Java application that has not used ConcurrentHashMap yet. The class was another implementation of Java .util.Map and a popular hash table data structure with concurrency inbuilt. This means you can also pass a ConcurrentHashMap to a method that is expecting a java.util.Map object. It was made scalable by dividing the whole map into a different segment, known as concurrency level, and then allowing threads to modify segments concurrently.

5 Free Linux Courses for Programmers and IT Professionals to Learn Online [2021]

Linux is one of the most popular operating systems to run server-side applications. I have seen almost all Java applications running on Linux, barring a couple of them, which run on Windows as a service. If you take out standalone apps like IDEs or tools, most of the real-world Java applications run on Linux, like payment gateways, trading systems, and other financial applications. That's why it's essential for any programmer, IT professional, or developer to learn and understand Linux, both the operating system, as well as the command line.

Polymorphism, Overloading, and Overriding in Java and Object Oriented Programming?

Polymorphism vs Overloading vs Overriding
Someone asked me the other day,  what are the difference between Polymorphism and Overriding in Java and the similar difference between Polymorphism and Overloading. After explaining to him personally, I thought to write a blog post about it and here we are. Well, they are not two different things, Polymorphism is an object-oriented or OOP concept much like Abstraction, Encapsulation, or Inheritance which facilitates the use of the interface and allows Java program to take advantage of dynamic binding in Java. Polymorphism adds flexibility to your code which makes it more extensible and maintainable.