Friday, March 1, 2024

Difference between known_hosts and authorized_keys file in SSH - Linux

If you have used SSH to login into remote host in Linux, you might have come across these two files stored under the .ssh directory in your home directory e.g. ~/.ssh. Both files are used in the login process for authentication, but the main difference between known_hosts and authorized_keys files are that, known_host is used for server authentication, while authorized_keys are used for client or user authentication. SSH allows login using both password and private keys, you might have heard about trusted SSH connection between two host to download files without entering password, this is achieved using public and private keys. 

2 ways to Split String with Dot (.) in Java using Regular Expression? Examples

You can use the split() method of java.lang.String class to split a string based on the dot. Unlike comma, colon, or whitespace, a dot is not a common delimiter to join String, and that's why beginner often struggles to split a String by dot. One more reason for this struggle is the dot being a special character in the regular expression. If you want to split String on the dot you need to escape dot as \\. instead of just passing "." to the split() method. Alternatively, you can also use the regular expression [.] to split the String by a dot in Java. The dot is mostly used to get the file extension as shown in our example.

Thursday, February 29, 2024

What is the ContextLoaderListener in Spring MVC? What does it do?

The ContextLoaderListener is one of the important component of Spring MVC framework. It is like any listener defined by Servlet specification and specified in web.xml using <listener> tag. It is loaded when Spring MVC based web application is deployed in any Servlet container e.g. Tomcat. The ContextLoaderLister of Spring MVC is responsible for loading root ApplicationContext for Spring. The application context is the place where Spring bean lives. If you need reference to a Spring bean either its auto-wired or injected by framework or you can get it directly from application context. In Spring MVC based web application, there can be multiple application context e.g. root application context and context local to each DispatcherServlet.

Thursday, February 15, 2024

Review - Is Grokking the System Design interview Course on DesignGuru Worth it?

Hello guys,  we are here again today for another exciting topic to discuss. But today, we will not discuss something related to Java or any other language or spring boot. Today, we will discuss something that is immensely practical and has the potential to land you very high-paying jobs. Today we are going to review a course that focuses on System Design! System Design is crucial for coding interviews! And it's also one of the most challenging topics to master. I have shared the best System design courses for coding interviews in the past. Today, I will review one of the top system design courses for technical discussions, Grokking the System Design Interview by Design Gurus.

Tuesday, February 13, 2024

Top 5 React and Redux Courses to Learn Online in 2024 - Best of Lot

If you are a Web developer or someone passionate about web development and looking for some awesome courses to learn React or React JS, a popular JavaScript framework to develop a component-based user interface then you have come to the right place. Facebook's React library has taken the front-end development world by storm. More and more people have started using React even in favor of Google's Angular, another popular front-end development framework. Well, I am not going into the classic debate of Angular vs React as both the framework has their own advantage and disadvantage but if you have chosen to learn React, you have made the right decision.

Monday, February 12, 2024

Top 10 System Design Courses for Beginners and Experienced Developers in 2024 - Best of Lot

Hello guys, if you are preparing for System design interview and looking for best online courses to learn essential System design concepts like load balancing, API Gateway, scalability, Microservices architecture as well as learn how to solve popular System design questions like how to design YouTube, WhatsApp, Parking Lot, Library System as well when to use NoSQL and SQL then you have come to the right place.  In the past, I have shared best System Design Books, Free System design courses,  System design prep guide, and System Interview Questions and in this article, I am going to share best System Design Courses for beginners and experienced Software Engineer to level up their System Design skills in 2024. 

Thursday, February 1, 2024

Top 6 Object Oriented Programming and Design Courses for Java Programmers in 2024 - Best of Lot

There is no doubt that Object-oriented programming is a pillar of software development and one of the reasons for the massive success of Java. Good knowledge of Object-oriented programming helps you to create better software. It also allows you to communicate your ideas better with your team members and fellow programmers. Despite being such an important technology, it's difficult to find programmers who understand OOP well. Many programmers just think that OOP is nothing more than Abstraction, Inheritance, Encapsulation, and Polymorphism, without genuinely understanding these concepts and mastering them.

Top 5 Courses to learn D3.js for Data Visualization with JavaScript in 2024 - Best of Lot

If you have done any Data visualization work then you might have heard about D3 - one of the excellent JavaScript libraries, which allows you to create beautiful interactive data visualization for the web. It's prevalent among Data Scientists and Data Analysts who often need these visualizations and charts to present data insights to stakeholders and business people. If you are not familiar with D3, no need to worry because, In this article, I am going to share some of the awesome courses to learn D3 in 2024. These courses teach you the basics of data visualization with D3 by binding data to a web page’s elements and customizing the elements based on that very data. You will also learn how to build different kinds of charts like Bar charts, Pie charts, Mind maps, etc using D3.js

Wednesday, January 31, 2024

Difference between List of ? (any type) and List of Object in Java Generics

No doubt that Generics is one of the most confusing topics in Java and you can easily forget concepts and rules, especially, if you don't code Java everyday. For example, both List<?> and List<Object> looks similar but there is a subtle difference between them, the List<?> is basically a list of any type, you can assign a list of String i.e. List<String> or list of Integer i.e. List<Integer> to it. You see the point, it uses the unbounded wildcard <?>, which means any type. It provides it the much needed Polymorphism require while writing Generic methods. Basically, if your method has a type List<?> which means you can pass any type of List to it but remember the type is unknown, until you assign it i.e. List<?> myList = new List<String>().