Top 5 Courses to Learn JavaFX Online in 2025 - Best of Lot

Hello guys, if you want to learn Java FX and look for the best Java FX courses, you have come to the right place. Earlier, I have shared the best Java Programming programming courses, and today, I will share with you the best online courses to learn Java FX from scratch. Java FX is the latest and greatest way for creating a GUI application in Java. There was a time when AWT and Swing was very popular for developing GUI based application in Java. Still, slowly Java Swing lost that place to C#, which became the standard language for developing desktop GUI and AWS lost the battle with Swing.

Top 5 Courses to learn iOS and Swift for Beginners in 2025 - Best of Lot

Hello guys, it's that time of the Year when we all start making our goals for better health, improving ourselves, and learning new things. Last Year, I focused mainly on the Web Development side and spent time teaching React, Angular, and Node JS, but this year, one of my goals is to explore the mobile world, particularly iOS and Android. At least that's a thought for now, and I am not sure how long I can go given the limited time I get to upgrade myself, but I'll try my best. Btw, suppose you also have the same goal and want to become an iOS developer in 2025. In that case, you should start your journey by learning iOS, Apple's Operating system, which runs on iPhone and iPad, and Swift 5, Apple's programming language for creating iOS apps.

Top 5 Online Courses to Improve Email and Workplace Writing Skills in 2025 - Best of Lot

One of my readers emailed me a couple of days ago and asked If I could suggest something to improve his email writing skills? He says that he is very good at work and programming but sucks on writing emails, and because of that, he never gets the visibility he deserved, resulting in no promotion or career growth. This sounds to be a prevalent problem, especially among programmers whose native language is not English, and who have never attended any business or email writing course. In fact, it was a problem for me as well, but I slowly picked it up though I am still far behind with many people I know who have excellent email communication skills.

Top 6 Free Courses to Learn Scala and Functional Programming in 2025 - Best of Lot

Scala is a powerful object-oriented and functional programming language long touted as the successor to Java or to replace Java. Well, that didn't happen in the last few years, but Scala has undoubtedly made a lot of progress and established itself as a scalable programming language for big things. If you are a social media user and know Twitter, then let me tell you that they are using Scala, which proves that Scala has all the tools you need to build a high-performance, scalable application like Twitter. Twitter is not the only company that is using Scala. If you look at Scala's website, you will find that IBM, Goldman Sachs, Verizon, and SAP use Scala to solve their problems.

Top 5 Courses to Learn Kali Linux in 2025 - Best of Lot

Kali Linux is an open-source Debian system based on Linux developed by the offensive security company for ethical hackers. It contains more than 400 tools categorized to make it easy for security researchers to analyze your network, test the system security, discover different vulnerabilities inside a web application, hide malware in apps, and target Android phones. If you want to learn Kali Linux and looking for the best online courses to learn Kali Linux on your own then you have come to the right place. Earlier, I have shared the best Ethical Hacking courses and Cyber Security Courses, and in his article, I am going to share the best Kali Linux courses for beginners. 

Top 10 Frameworks to become a Full Stack Developer in 2025 - Best of Lot

The Technical world changes as fast the technology changes, and so are the technical jobs. Gone are the days where you can land a job by just knowing one technology or programming language, and somehow survive in the position for many years without learning new things. Many of us get into the programming and web development world by knowing just one or two technology like Java, C++, or JavaScript, but that won't cut the ice anymore. There were teams of tens of people doing specialized jobs like front-end development is done by a separate set of developers and back-end is written by other sets of programmers, commonly known as server-side developers.

Top 10 Angular Tutorials and Courses for Web Developers in 2025 - Best of Lot

Hello guys, if you are interested in learning the Angular framework in 2025, one of the best and most popular JavaScript frameworks for developing component-based Web GUI, and looking for some awesome courses, books, and tutorials then you have come to the right place. Earlier, I have shared the best Angular courses and In this article, I am going to share some of the best resources like books, tutorials, and courses to learn the Angular framework, formerly known as Angular, and now famous as Angular 2. It's backed by Google; hence you should not worry about it being outdated and losing relevance in a couple of years. Any investment you made in learning Angular will pay you rich dividends in the coming years.

Top 5 Online Courses to Learn C Programming in 2025 - Best of Lot

Hello guys, today, I will talk about one of the oldest, reliable, powerful programming languages that have survived for 50 years. Yes, that's right, 50 years. It's a great achievement for any technology to remain relevant for such a long period. If you don't know, the C Programming language is one of the first general-purpose programming languages, invented by Dennis Ritchie and Ken Thomson around 1969. Ken was writing UNIX, another accessible technology that has survived for 50 years around the same time and needed a programming language that can do all kinds of tasks; the result was a C programming language.

Top 5 Courses to Learn Recursion for Dynamic Programming in 2025 - Best of Lot

Hello guys,  if you want to learn and Master Recursion and looking for the best resources like books, online courses, and tutorials then you have come to the right place. Earlier, I have shared the best dynamic programming courses, and 15 Recursion exercises for beginners, and today, I am going to share the best courses to learn Recursion for beginners. Recursion is the process by which a function calls itself again and again directly or indirectly. These types of functions are called recursive functions. All successful software programmers need to have an understanding of how recursive functions work as well as how to build recursive functions. 

Top 10 Free Courses to learn Spring Framework and Spring Boot in 2025 - Best of Lot

Hello guys, if you want to learn Spring Framework and looking for best online resources like books, courses, and tutorials then you have come to the right place. Earlier, I have shared best Spring Framework courses, books, and Spring interview questions and in this article, I am going to share best free courses to learn Spring framework in 2025. When I shared the list of best Spring Courses, a lot of you asked me about free spring courses and this article is the result of that research, but before we get to the 10 best free Spring courses that are perfect for beginners, let me tell you more about what the Spring Framework really is.

Top 8 Courses to Learn about NFTs (Non Fungible Tokens) in 2025 - Best of Lot

Hello guys, if you want to learn what is NFT or Non Fungible Token and what is the buzz around NFT, and have questions like should you create and sell NFT etc then you have come to the right place. Earlier, I have shared best online courses to learn Blockchain and crypto currencies and in this article I am going to share best online courses to learn NFTs, but before that, let's understand what is NFT?  NFTs or else known as Non-Fungible Tokens are a form of digital art. Non-Fungible basically means that they are unique. If you own one NFT, there’s nothing else in this world that is the same as yours. Nothing! That uniqueness and sense of ownership is driving crazy sales with recent reports suggesting that NFT sale clocking at around $70 million and increasing exponentially.

Top 10 Udemy Courses for Python, JavaScript and Web Development in 2025 - Best of Lot

Hello guys, Udemy, one of the most popular online learning platforms, is known for its sale where you can buy a $200 course for just $10, and they are running a sale now. It's actually an excellent time to buy some quality courses as you won't get another chance to buy the course at a price as low as $9.9, but the big question is which courses you should buy on Udemy in 2025? I always purchase courses from the reputed instructor and teach evergreen and in-demand skills like Java, Python, Microservices, Docker, Kubernetes, and AWS. I generally buy a lot of courses in Udemy sales and then access them whenever I need them. Though, I must warn you Udemy is addictive, and I often buy more classes than I need, so beware of that and buy courses you need now or shortly.  

Top 5 Courses to Learn Spring Data JPA Courses in 2025 - Best of Lot

Hello Java programmers, if you want to learn Spring Data JPA in 2025 and looking for the best online courses then you have come to the right place. Earlier, I have shared my favorite courses to learn different projects under Spring frameworks like Spring Boot, Spring Cloud, Spring Security, Reactive Spring + WebFlux,  and Spring MVC and in this article, I am going to share the best Spring Data JPA courses for beginners and experienced Java developers. Spring Data JPA is part of Spring Framework and it really makes it easy to work with JPA providers like Hibernate and EclipseLink. It can greatly improve developer productivity if used correctly.

Top 5 Courses to Learn Dynamic Programming for Coding Interviews in 2025 - Best of Lot

Hello guys, If you are looking for a job and giving interviews then you might have noticed that getting a Software development Job is becoming more and more difficult every day. For example, there was a time when you can get a Java developer position by just knowing Core Java concepts like String, Collections, and Multithreading, etc, but, not anymore. There were definitely some questions on Data structure and Algorithms and even on Dynamic Programming at that time as well, but the focus was always on programming language expertise like Java or Python. But, things have completely changed now, and the focus is more and more on the candidate's ability to solve coding problems.

Top 6 Free SQL Courses for Beginners to Learn Online in 2025 - Best of Lot

Hello guys, we are already in the second week of New year, and everyone is talking about their goals to improve them as a better person, a better programmer, or better health. If you have also made your goal, and one of them is to improve your SQL skill, you have come to the right place because I will share some of the free online courses to learn and master SQL this year. The list includes a free course from Udemy, a popular online portal to learn Oracle, PostgreSQL, and Microsoft SQL Server. Yes, I have tried hard to include free courses on different databases to choose the course you want. 

Review - Is Coursera Plus worth it in 2025? (New Year SALE $200 OFF - 50% Discount Now)

Hello guys, as a programmer, we always need to learn new skills like Generative AI, frameworks, technologies, and libraries, and we often end up buying so many courses for that; I know people who have more than 300 courses on Udemy and other online courses platforms, but Coursera now has a better way, Coursera Plus. This is a subscription plan for Coursera courses and specializations, which will provide you access to their 10000+ courses, guided projects, specialization, and professional certificates with just one subscription. 

Top 8 C++ Online Courses for Beginners to Learn in 2025 - Best of Lot

Hello guys, If you want to learn C++ and looking for some awesome courses and books then you have come to the right place. Earlier, I have shared the best C programming courses, as well as free C++ courses, and the best C++ books for advanced programmers and In this article, I am going to share some of the best courses to learn C++ from scratch. These are the truly great courses from Udemy, Coursera, Pluralsight, and Educative and you can join them to learn C++ online from your home. If you are new to the programming world or have been coding for some time then you know that C++ is one of the most popular and widely used programming languages. It was the first major object-oriented programming language that was used widely by the software development industry as well as in Academia.

Top 7 Courses to Learn UI and UX Design in 2025 - Best of Lot

Hello guys, If you always wanted to learn UX design and become a UX designer and looking for the best UI/UX design online courses to start with, then you have come to the right place. In the past, I have shared the best web design courses, best Figma courses, one of the popular UI design tool, and web development courses, and In this article, I will share the best UX online courses and certifications you can join to become a UX designer in 2025. The demand for UX/UI and Web Design professionals continues to increase in today's job market. Learning UI or UX skills can open doors to many jobs, both local and remote.  It goes without saying that certification in any discipline will give you a leg up on your job hunt.

Top 7 Python Data Structures and Algorithms Courses in 2025 - Best of Lot

Hello Python developers, if you want to learn Data structure and Algorithms in the Python Programming language and look for the best online courses, you have come to the right place. In the past, I have shared a lot of valuable resources like free data structure courses, books, and tutorials to learn Data Structure and Algorithms for programmers. I have also shared a lot of Algorithmic interview questions and their solutions in Java. Still, I have constantly been getting queries about good courses to learn Data Structure and Algorithms in Python and JavaScript. Even though the topics are completely independent of the programming language, Python developers definitely like the classes and books that teach Python's data structure and algorithms.

Top 5 Online Courses to Learn Coding and Software Development in 2025 - Best of Lot

Programming and/or Coding is one of the essential skills for today's technological world, and awareness of coding is growing every passing day. In my time, about 20 years back, I only learned to code when I entered engineering college to pursue Computer Science and Engineering degree, but things have changed a lot since then. Nowadays, even kids have started learning to code, even my daughter can code, and much better than what I can also do in college. More accessible computing gadgets like iPad, iPhones, smartphones, and Laptops have genuinely changed the environment and made Coding or Programming more accessible.

6 Free DevOps Courses for Experienced Developers in 2025 - Best of Lot [UPDATED]

Hello Java Programmers and developer friends, If you are an experienced developer and want to become a DevOps Engineer or just want to learn the DevOps process and tools to improve your development and delivery process and looking for free DevOps online courses to kickstart your journey, then you have come to the right place. Earlier, I shared the best DevOps books and training courses, and today, I will share the best free online lessons to learn about DevOps. These free courses are created by experts and trusted by thousands of developers and they will teach you DevOps concepts, practice, DevOps tools like Docker, Jenkins, Ansible, and Kubernetes and suitable for both beginners and experienced developers. They are also curated from popular online learning platforms like Udemy, Pluralsight, and Coursera, and they offer practice and hands-on training.

Top 10 Coursera Courses and Certifications for Java Developers in 2025 - Best of Lot

Hello guys, if you are looking to learn Java on Coursera, one of the most reputed online course platforms and looking for the best Courser courses for Java Developers then you have come to the right place. Earlier, I have shared the best Java development courses from Udemy,  Pluralsight, and LinkedIn Learning, and today, I am going to share Java courses from Coursera. The list includes both beginner-level and advanced-level Coursera courses for Java developers. This means you will not only find courses to learn core Java but also courses to learn advanced concepts like concurrent programming, distributed programming, Microservices, and Spring Framework. 

9 Blockchain Courses & Certifications For Beginners in 2025 - Best of Lot

Hello folks, if you are not living under the rock, you would have definitely heard about Blockchain and Cryptocurrencies. Blockchain is one of the most in-demand skills, and there are not many people out there. If you want to learn Blockchain and related technologies like Ethereum, Solidity, Hyperledger, etc., and are looking for Blockchain training courses and certification, you have come to the right place. But, before that, let's get a quick overview of what Blockchain is, why it's popular, and why you should learn Blockchain in 2025.

13 Advanced Spring Framework Courses for Experienced Developers in 2025 - Best of Lot

Hello guys, if you are a Java developer and want to learn Spring Framework in-depth and looking for some advanced Spring online courses to learn things like Spring Boot, Spring Cloud, Spring Data JPA, Spring Security, Spring MVC, etc then you have come to the right place. Earlier, I have shared the best courses to learn Spring Boot, Microservices, and Hibernate and JPA and in this article, I am going to share the best and advanced Spring Framework courses for experienced Java developers. There is no doubt that the Spring framework is probably the most important skill for Java developers, but just knowing Spring is also not enough. 

Top 6 Online Courses to Learn Flutter in 2025 - Best of Lot

If you are like me, who thinks Flutter is the future of mobile development and looking for some excellent online courses to learn Flutter, then you have come to the right place. In this article, I am going to share some of the best online courses to learn Flutter in 2025 from Udemy, Pluralsight, and Coursera, but before going into that, let's see what Flutter is and why everyone is so excited about it. Well, in general, whenever something comes from Google, it makes a lot of developers excited like Angular, Dart, and now Flutter. I have got my hand dirty in both Android and iOS using Java and Objective-C in the past, but after working for some time, I decided to move on.

Top 10 Free Courses to Learn Python in 2025 - Best of Lot

There is no doubt that Python is currently the world's #1 programming language and the biggest advantage of that is it's bringing more and more people into the programming world. In recent years, I have seen more people learning Python than any other language, yes, not even JavaScript. Many of them learning Python to explore some awesome Data Science and Machine learning libraries provided by Python. Some people are also learning Python for web development and there are still many developers who are learning Python for scripting and automating trivial tasks. It doesn't matter why you are learning Python at this moment, it's a great thing in itself that you have decided to learn Python.

5 Best Spring Security Online Training Courses for Java Developers (2025)

Hello Java developers Spring Security is one of the leading open-source, security frameworks that allow you to implement security in Java-based web applications. It provides several security features like authentication, authorization, the remember me functionality out-of-the-box, which means you can directly use them without adding code or changing your class. Yes, Spring Security implements security at the application level i.e. you can even secure your non-secure resource without modifying them. It is also the leading framework to secure RESTful Web Services. Because of all these, the demand for Java developers with good knowledge of Spring Security is very high.

Top 10 Online Courses to Crack Coding Interviews in 2025 - Best of Lot

To be honest with you, getting your first job is never easy. It is, in fact, the most laborious task, and you need to put your best effort into finding a role in your dream company. Most of the computer science graduates dream of working for Google, Facebook, Amazon, Microsoft, and Apple, but they are often not able to clear their rigors coding interviews. The single most important reason for failing those coding job interviews is a lack of knowledge and practice; hence, it becomes increasingly important that you prepare hard in advance. Unfortunately, I learned this little too late after spoiling my chances at Microsoft and Amazon, but you can learn from my experience and prepare better for your programming job interviews.

Top 8 Courses to Learn Terraform in 2025 - Best of Lot

Hello folks, if you have done infrastructure deployment like creating a server, installing applications, and creating a production environment then you know that deploying and maintaining traditional infrastructure is a manual task fraught with repetitive tasks, inconsistent configuration, and always out-of-date documentation. Terraform is an essential DevOps tool that is used to version infrastructure as code. If you want to learn Terraform in 2025 then you have come to the right place. In the past, I have shared the best DevOps courses and best online courses to learn essential DevOps tools like Docker, Jenkins, and Kubernetes, and today I am going to share the best online courses to learn Terraform in 2025. The list contains courses for both beginners and experienced engineers.

Top 10 Courses to Crack Java Interviews in 2025 - Best of Lot

Hello guys, if you are preparing for Java interviews like for a core Java developer role in a big Investment bank like JP Morgan, Morgan Stanley, etc., or a Java web developer in service-based companies like Infosys, TCS, Luxoft, Tech Mahindra, IBM, and Cognizant, and looking for some awesome courses and material, then you have come to the right place. Earlier, I have shared the best coding interview courses which focused on essential coding interview skills like Data Structure and Algorithms, SQL, Linux, etc.  While those are still very good to prepare for any coding interview, including the Java developer role and you can use them to build your programming fundamentals.

Top 5 Java Multithreading and Concurrency Courses for Experienced Programmers in 2025 - Best Of Lot

If you are a Java developer and looking for some awesome resources e.g. books and courses to improve your multi-threading and concurrency skills in Java then you have come to the right place. In the past, I have shared books and tutorials on Java Concurrency and Multithreading, and in this article, I am going to talk about some of the best free and paid courses to learn multithreading and concurrency in Java. You can join these free courses to improve your understanding of Java Concurrency and Multithreading. It's one of the most important skills for Java developers as almost all the companies who interview Java developers pay particular attention to their knowledge and experience in this area.

Top 5 Online Courses to Learn MongoDB NoSQL Database in 2025 - Best of Lot

MongoDB is one of the leading NoSQL databases and it was on my radar for a long time but I never get a chance to learn or work on it, but Recently I got an opportunity to use MongoDB for one of our projects and I learned a lot on the way. In this article, I will introduce MongoDB and how to learn MongoDB so that you can use it in your project. In this article, I will share some of the online courses which I have taken to understand everything up to the basic CRUD (Create, Retrieve, Update, Delete) operations on MongoDB. I have also read a couple of books and followed some tutorials but these courses were my main source to learn Mongo DB.

Top 5 Online Courses to learn gRPC and Google Protobuf in Java, Python, Golang & C# in 2025 - Best of Lot

If you are a Java developer then you might have heard about the gPRC, the Google Remote Procedure Call solution. It's the latest buzz in the tech circle, and people are talking enthusiastically about it. The buzz is evident because it's coming from Google like Angular, Golang, Flutter, Dart, TensorFlow, and other latest technologies. For those who don't know, gRPC is a super-fast, super-efficient Remote Procedure Call (PRC) system that will help you to develop distributed systems like Microservices. This means you can use gPRC to communicate between your Microservices at super-fast speed.  Similar to other RPC solutions like SOAP, it allows a client application to call a method on the server as it is a local object. The server defines service and indicates that it can be called remotely with method parameter and return type and then provides implementation and an RPC server that can handle client calls.

Top 7 Courses to learn Data Structure and Algorithms in 2025 - Best of Lot [UPDATED]

Hello guys, both Data Structures and Algorithms are one of the most essential topics for programmers and if you want to learn Data Structure and Algorithms in 2025 then you have come to the right place. The best thing about them is that they never get out-of-date, and any investment you made in terms of time and money will pay rich dividends for a long time. I have also found that people good at algorithms and data structures are often better programmers than others. They tend to improve your programming skill and coding sense, and that's the main reason I suggest all kinds of programmers, from junior to senior to spend some time revising, refreshing, and honing their data structure and algorithm skills.

Top 10 Object-Oriented (OOP) Design Principles Java Programmers Should Know

The Object-Oriented Design Principles are the core of OOP programming, but I have seen most of the Java programmers chasing design patterns like Singleton pattern, Decorator pattern, or Observer pattern, and not putting enough attention on learning Object-oriented analysis and design. It's essential to learn the basics of Object-oriented programming like Abstraction, Encapsulation, Polymorphism, and Inheritance. But, at the same time, it's equally important to know object-oriented design principles. They will help you to create a clean and modular design, which would be easy to test, debug, and maintain in the future.

How to Print Duplicates from a Given String in Java? [Solved]

Problem : You have given an input String, write a program to print all the duplicates from input String. For example if given String is "Java" then your pogrom should print "a", and if given String is "C++" then your program should print "+". If String doesn't contain any duplicate then it should print nothing e.g. if you pass "Python" or "Ruby", it should print nothing. 

How to find the largest and smallest number in given Array in Java? Example Tutorial

Hello guys, today I am going to discuss one of the frequently asked programming interview questions to find the largest and smallest number from an integer array. This question is commonly asked on telephonic interviews and the first round for screening candidates. This coding problem is in the same league of other frequently asked algorithmic questions like Fibonacci, Palindrome, Prime, and Power of two checks. They are easy but you will find them difficult during the interview because of the pressure, particularly if you have not solved them before. Sometimes even if you have solved the problem one time, you tend to do mistakes because you haven't understood them properly. So, always take your time to understand the question.

Top 20 Amazon and Google Programming Interview Questions for Software Developers

Hello, In this article I am going to sharing some frequently asked programming job interviews from technical giants and startups. If you are going for a programming job interview with Microsoft, Google, or Amazon, you better be prepared for all kinds of questions. These companies are known to ask tough questions, tricky puzzles, and lots of data structure and algorithm questions. Since it's hard to prepare all these in a short time, it makes sense to at least have a good idea of frequently asked programming questions in Microsoft, Google, or Amazon.

Polymorphism and Inheritance Example in Java

Hello guys, If you are new to Java or Object oriented programming and wondering what is Polymorphism and Inheritance and what are their use then you have come to the right place. Polymorphism and Inheritance are two fundamental concepts in object-oriented programming that allow for flexibility and reusability of code. In Java, these concepts are closely related and often go hand in hand. Java Programming provides a couple of way to implement Inheritance like extending a class or implementing an interface. Similarly they provide overloading and overriding for Polymorphism. In the past, I have shared 40 object oriented questions as well as 23 design patterns and In this article, we'll explore these concepts with a practical example.

How to fix java.lang.NoSuchMethodError: main Exception in thread "main" in Java? Example

How to solve java.lang.NoSuchMethodError: main Exception in thread "main"

java.lang.NoSucMethodError comes when Java code tries to call a method that does not exist on a class, this could be either static or non-static method. a most common manifestation of java.lang.NoSuchMethodError is running a class that doesn't have the main method in Java. In this article, we will see what is "java.lang.NoSuchMethodError: main Exception in thread "main"", Why does java.lang.NoSuchMethodError comes and how to solve java.lang.NoSuchMethodError in Java.

How to deal with NullPointerException in Java with Examples - java.lang.NullPointerException Guide

The java.lang.NullPointerException or NullPointerException in Java is probably the first error or exception you will face in Java. It is a true nightmare for beginners in Java but pretty easy to solve once you get familiar with Exception handling in Java. What makes NullPointerException a little bit tricky to solve is its name which has a pointer in itself and Java does not support pointers like C++ or C, just like you don't have multiple inheritances in Java. As a Java developer with 20 years of experience, I have solved countless amount of NullPointerException and now I have developed a coding and debugging sense through which I can spot what causing a particular NullPointerException and how to fix it. 

Difference between transient and volatile keyword in Java? example

Surprisingly "Difference between transient and volatile keyword in Java" has asked many times on various java interviews. volatile and transient are two completely different keywords from different areas of Java programming language. the transient keyword is used during serialization of Java object while volatile is related to the visibility of variables modified by multiple threads during concurrent programming. The only similarity between volatile and transient is that they are less used or uncommon keywords and not as popular as public, static, or final.

Why wait, notify, and notifyAll methods are called from synchronized block or method in Java?

Most of the Java developers know that wait(), notify(), and notifyAll() methods of object class must have to be called inside synchronized method or synchronized block in Java but how many times we thought why? Recently this question was asked to in Java interview to one of my friend, he pondered for a moment and replied that if we don't call wait() or notify() method from synchronized context we will receive IllegalMonitorStateException in Java. He was right in terms of the behavior of language but as per him, the interviewer was not completely satisfied with the answer and wanted to explain to him more about it.

The multi-part identifier XXX could not be bound in SQL SERVER [Solution]

Problem, I was doing join statement and getting this error Msg 4104, Level 16, State 1, Line 69

The multi-part identifier "a.X" could not be bound."

Cause:

I was mixing implicit joins with explicit joins. That is allowed, but you need to be aware of how to do that properly.

The thing is, explicit joins (the ones that are implemented using the JOIN keyword) take precedence over implicit ones (the 'comma' joins, where the join condition is specified in the WHERE clause).

Difference between Wait and Sleep, Yield in Java? Example

The difference between wait and sleep or the difference between sleep and yield in Java is one of the popular core Java interview questions and asked on multi-threading interviews. Out of three methods that can be used to pause a thread in Java, sleep() and yield() methods are defined in thread class while wait() is defined in the Object class, which is another interview question. The key difference between wait() and sleep() is that the former is used for inter-thread communication while later is used to introduced to pause the current thread for a short duration. 

Difference between Thread vs Runnable interface in Java

Thread vs Runnable in Java is always been a confusing decision not just for beginners in Java but also for developers who have done a couple of projects in Java. Thread in Java seems easy in comparison to Runnable because you just deal with one class java.lang.Thread while in case of using Runnable to implement Thread you need to deal with both Thread and Runnable two classes. though the decision of using Runnable or Thread should be taken considering differences between Runnable and Thread and the pros and cons of both approaches.

What are AtomicInteger and AtomicLong in Java? How it works? compareAndSet() Example Tutorial

Concurrency is a fundamental aspect of modern software development, and Java provides a variety of tools and classes to help developers manage shared resources and coordinate the behavior of multiple threads. Among these tools one is atomic variables, which ensure that certain operations on shared data are performed atomically, I mean in one shot, without the need for explicit synchronization. In the past I talked about difference between atomic, synchronized, and volatile in Java and In this article, we'll explore atomic variables in Java, with a focus on AtomicInteger and AtomicLong, and explain how they work and how to use them effectively in Java. 

6 ways to get the selected text from html drop down list in jQuery?

One of the common task in web development is retrieving the selected text from a drop down list, which is nothing but HTML select element. This allows users to choose one of the options presented, each text is enclosed in option tag. how can we retrieve the selected text using jQuery? Well, there are multiple ways but core is first find the select element than the selected option by using :selected pseudo class selector. 

How to get the selected radio button on click using jQuery? Example

In last couple of articles, you have learned how to get all checked checkbox and how to find the unchecked checkbox using jQuery, let's see another similar example, this time with radio button. Suppose, in form you have two radio buttons to select the gender i.e. male and female. How do you find which radio button was selected when user clicked on them? well, we will use the jQuery selector to find that. In fact, its not much different than what you have used to find the checked checkbox i.e. $("input[type=radio]:checked") will give the selected radio button. In order to find the chosen radio button when user click, you need to bind a click handler. Let's see an example. 

How to enable/disable form elements using jQuery? Examples

In last couple of tutorials you have learned how to get all selected checkbox and radio buttons, and in this tutorial, you will learn how to enable/disable form elements using jQuery. A form element e.g. a textfield, radio buttons and checkbox, all represented using input tag can be enabled or disabled by adding an attribute called "disabled". It's similar to "checked" attribute we have seen for checkbox and radio buttons. If this attribute is not present then element is enable, but if this attribute is present then you can use disabled=true to disable the form element and disabled=false to enable the form elements as shown in our example. 

How to convert XML to JSON in Java? Example

Since XML and JSON are two popular data interchange formats, you will often need to convert one into other. For example, many SOAP web services returns XML response and if you are using Java and wants to convert that XML response to JSON, then you can use JSON library from https://json.org. It provides a class called XML.java, which provides static methods to convert an XML text into a JSONObject. It also support JSON to XML conversion, which will learn in second part of the article. In order to use this class, you can dowload JAR files from Maven Central repository, or you can add required dependency in your pom.xml file. 

How to convert JSON String to Java HashMap? Example

Suppose you have a JSON String, may be a web-service response and you want to create a Map out of it, where key should be the fields and value should be values of those fields e.g. if given JSON String is following :

{

"zip": "90210",

"city": "Beverly Hills"

"state": "CA"

"timeZone": "P"

}

then your HashMap should contain 4 mappings where keys are zip, city, state and timeZone, all of String type and corresponding values. 

What is Timer and TimerTask in Java – Tutorial Example

Timer in Java is a utility class that is used to schedule tasks for both one time and repeated execution. Timer is similar to the alarm facility many people use in mobile phones. Just like you can have one time alarm or repeated alarm, You can use java.util.Timer to schedule a time task or repeated task. In fact, we can implement a Reminder utility using Timer in Java and that's what we are going to see in this example of Timer in Java. Two classes java.util.Timer and java.util.TimerTask is used to schedule jobs in Java and forms Timer API. 

4 Reasons and Benefits of Using Multithreading in Java? Why Threads?

In one word, we use Threads to make Java applications faster by doing multiple things at the same time. In technical terms, Thread helps you to achieve parallelism in Java programs. Since CPU is very fast and nowadays it even contains multiple cores, just one thread is not able to take advantage of all the cores, which means your costly hardware will remain idle for most of the time. By using multiple threads, you can take full advantage of multiple cores by serving more clients and serving them faster. Since, in today's fast-paced world, response time matters a lot and that's why you have multi-core CPUs, but if your application doesn't make full use of all resources then there is no point adding them, multi-threading is one way to exploiting huge computing power of CPU in Java application.

4 examples to convert Date to LocalDate in Java 8?

One of the challenge you will face while using new Java 8 Date and time API, JSR-310 in existing Java application is the conversion between java.util.Date and java.time.LocalDate and other classes. Even though library has everything you would expect, it doesn't have a direct conversion method between old Date and new LocalDate. There is a reason for it, eventhough java.util.Date says its a date its not, becuase its just a millisecond value since midnight at the start of 1970 GMT. It's equivalent to Instant class in new Java Date API and that's why you have a direct conversion method between Date and Instant in Java 8. Anyway, its not hard to convert a java.util.Date to java.time.LocalDate in Java 8, in fact there are multiple ways which we will explore in this tutorial. 

Difference between ExecutorService.submit() and Executor.execute() methods in Java?

What is the difference between Executor.submit() and Executor.execute() method in Java? This is one of the good multi-threading questions for experienced Java programmers, mostly asked in Investment Banks like Barclays, Deutsche Bank, or Citibank. A main difference between the submit() and execute() method is that ExecuterService.submit()can return the result of computation because it has a return type of Future, but the execute() method cannot return anything because return type is void. The core interface in Java 1.5's Executor framework is the Executor interface which defines the execute(Runnable task) method, whose primary purpose is to separate the task from its execution.

Difference between Process and Thread in Java - Example

One of the common questions from programming interviews is, what is the difference between a Thread and a Process? Well, the main difference between them is that a Process is a program that is executing some code and a thread is an independent path of execution in the process. A process can have more than one thread for doing independent tasks e.g. a thread for reading data from disk, a thread for processing that data, and another thread for sending that data over the network. This technique to improve throughput and better utilize CPU power is also known as multi-threading.

How to use Exchanger for Inter thread communication in Java? Example Tutorial

Hello guys, if you are working in a concurrent Java application then you might have heard about the Exchanger class of java.util.concurrent package. The Exchanger in Java is another concurrency or synchronization utility introduced in Java 1.5 along with CountDownLatch, CyclicBarrier, and Semaphores. As the name suggests, the Exchanger allows two Threads to meet and exchange data at the rendezvous or meeting point. This means you can use Exchanger to share objects between threads and for inter-thread communication. The java.util.Exchanger is a parametric class, which defines and holds the type of object to be exchanged. It has an overloaded method called the exchange(), which is used to exchange objects between threads.

What happens when you call Thread.run() instead of Thread.start() in Java? Trick Interview Question

Hello guys, writing multi-threaded and concurrent programs is not easy, not even in Java.  Even senior developers, including myself, make mistakes while writing concurrent Java applications. This is also one of the trickiest areas of Java programming language, where misconceptions outnumber concepts. Considering the amount of misconception an average Java programmer has about multi-threading and concurrency, I thought to start a new series about common multi-threading mistakes done by Java programmers; what is a better way to learn from common real word mistakes.

How to Implement Thread in Java with Example

How to implement Thread in Java
In my opinion, Thread is one of the most important features of the Java programming language which helped it to become the most popular programming language. I remember, when I first started learning Java in one of the programming classes in India how important Thread was a portrait and how much emphasis is given on a clear understanding of multi-threading. It’s still popular and one of most sought after skills in Java programmer because writing concurrent and multi-threaded applications in Java is challenging, despite Java providing excellent support at language level using synchronized and volatile keyword.

Udemy vs Educative Review? Which is better Website for Beginners?

Hello guys, if you are wondering the difference between Udemy and Educative and whether you should take Udemy courses or join the Educative platform to learn new tech skills, you have come to the right place. Earlier, I have shared a comparison between Pluralsight and Udemy as well as CodeCademy vs Pluralsight in this article, I will compare Udemy with Educative, a new text-based, interactive learning platform. While I have often said that Udemy is my favorite platform because you can get high-quality and comprehensive courses from top instructors for just $9.9, which is phenomenal. 

Can You Learn Coding and Web Development in your 40s and 50s?

Yesterday, I was speaking to one of my friends who were not from a programming background but working as a teacher in a college of Engineering and Technology in the countryside of India. He just turned 40, and he is also the father of two wonderful kids. He has been teaching Maths to B.Tech students in a private engineer college for the last 15 years. He is earning Ok, but he always wanted to explore the world, and he now realizes that a Programming job can provide him that opportunity, so he contacted me to find out whether it's too late for a Programming career.

Review - Is Grokking the Machine Learning Interview on Educative Worth it in 2025?

Hello friends, we are here again today for another exciting topic to discuss. But, today we are not gonna discuss something which is related to Java or any other language or spring boot. Today we are gonna discuss something which is immensely practical and has the potential to land you very high-paying data science jobs.  Today we are gonna review a course that focuses on Machine Learning! Machine Learning is very important when we are considering data science interviews! So what's the wait? Let's start! On Educative.io, there is a great course called Grokking the Machine Learning Interview. It couldn't have come at a better moment, with machine learning expected to be a $3.6 billion business by 2025.

5 Projects You can do to learn iOS App Development in 2025

Hello guys, if you are learning iOS App development and looking for some project ideas to better learn the concepts and apply your existing knowledge then you have come to the right place. Earlier, I have shared the best iOS and Swift courses, and today, I am going to talk about 5 cool projects you can do to learn iOS app development and master several key concepts like UI, Core ML, Speech to ext, and other APIs. Since it's very common for people to get stuck while doing projects, I have also included guide courses, both free and paid which you can join to learn how to do these projects step by step. 

Coursera's Google IT Automation with Python Certification Review - Is it worth it in 2025?

Hello guys, if you are joining Google IT Automation with Python Professional Certification on Coursera and want to find out whether it's worth your time and money or not then you have come to the right place. Earlier, I have shared the best Coursera Certifications and a review of other popular Google courses on IT support and in this article, we'll review Google's most popular Python certification course in Coursera. Google's IT automation with Python is a professional certificate and more than 575,000 people have already joined this course it's from Google which is a great sign but you will find out more about this course in this review. 

Udemy's The Data Science Course: Complete Data Science Bootcamp 2025 Review - Is it worth it?

Hello guys, if you want to learn Data Science and looking for the best courses or want to join The Data Science Course 2025: Complete Data Science Bootcamp course on Udemy but are not sure whether this course is right for you then you have come to the right place. Earlier, I have shared the best Data Science courses and in this article, I am going to review this popular Udemy course to learn Data Science in 2025. This is one of the most popular Udemy courses when it comes to learning Data Science and with more than 560K students it's right there with the Data Science A-Z course by Kirill Eremenko, my favorite Udemy instructor for Data Science and Machine Learning. 

Top 25 Skills Java Developers Should Learn in 2025 [UPDATED]

Hello guys, recently I was doing some research on what skills Java developers should learn in 2025 to become a better developer and give their career a boost and I found some interesting skills like Kafka and  Elastic Search, apart from obvious ones like Spring Boot and Microservices. One of my favorite places for doing such research is examining Job listings on LinkedIn from different companies like Investment banks, Service-based companies, startups, and mid-tier companies where Java is used extensively. When I saw those skills, I can immediately tell that those are really useful and worth sharing with you guys, as I have often seen those skills playing important roles while hiring Java developers.

6 Tips to write Production Quality Code

We often hear the term "production quality code", some times in an interview where the interviewee asked to write production-quality code for a particular function, sometimes discussion between developers and programmers and sometimes during code review. I know most of you familiar with the term but for those who wonder what is production quality code in simple terms its code which can bear the test of time in a production environment. We all develop code in development, then test in QA and finally, it gets released in production.

Top 10 Multithreading and Concurrency Best Practices for Experienced Java Developers

Writing concurrent code is hard and testing correctness with concurrency is even harder. Though Java programming language provides lots of synchronization and concurrency support from language to API level, it eventually comes to an individual's diligence and expertise to write bug-free Java concurrency code. These Java concurrency and multi-threading best practices are a collection of some well-known tips, which help you to write better concurrency code in Java. Some of you may be familiar with these tips but it's often worth revising them time and time again. 

How to find Square root of integer in Java without using any Library? Interview Question

Problem : Given an integer i, find square root of it, without using Math.sqrt() method. Your method should return square root if given number is perfect square otherwise return floor(sqrt(x));

For example, 

Input i = 16

Output : 4

Input i = 17

Output : 4

This is very interesting problem and asked both freshers and experienced programmers. I have seen this question on many companies including ANZ, Barclays, and Citibank.

How to print Floyd's Triangle in Java? Example Tutorial

There are lots of programming exercises in Java, which involve printing a particular pattern in the console, one of them is printing the Floyd triangle in the console. In the Floyd triangle, there are n integers in the nth row and a total of (n(n+1))/2 integers in n rows. This is one of the most simple patterns to print but helpful in learning how to create other more complex patterns. The key to develop patterns is using nested loops and methods like System.out.print() and println() appropriately. Actually, pattern-based programming tasks are originally designed to master loops in programming.

How to Check if two Rectangles Overlap in Java? Collision Detection Solution and Example

Can you write a Java program to check if two rectangles are overlapping with each other or not? is one of the frequently asked coding questions on tech giants like Facebook, Amazon, Microsoft, and others. This is also a kind of problem where it's easy to find opposite or negative conditions like when rectangles are not overlapping and then inverting the result to prove that rectangles are colliding with each other. I first heard about this problem from one of my friends who were in the Android game development space. He was asked to write an algorithm to find if given rectangles are intersecting or not.

Linux Command to Find how Long a process is Running in UNIX - Example

Hello guys, today, I am going to share one of the useful tips to find out how long a particular process is running in Linux. This is very useful while you are troubleshooting an issue and want to know whether your process or service is restarted fine on a daily or weekly basis. So you checked your process is running in Linux operating system and it's running fine, by using ps command. But now you want to know, from how long process is running, what is the start date of that process etc. Unfortunately, PS command in Linux or any UNIX based operating system doesn't provide that information.

Difference between FileInputStream and FileReader in Java | InputStream vs Reader Example

Before going to explain specific difference between FileInputStream and FileReader in Java, I would like to state fundamental difference between an InputStream and a Reader in Java, and when to use InputStream and when to go for Reader. Actually, Both InputStream and Reader are abstractions to read data from source, which can be either file or socket, but main difference between them is, InputStream is used to read binary data, while Reader is used to read text data, precisely Unicode characters.

4 Ways to Convert String to long in Java? Example Tutorial

How to convert a string to long in Java is one of those frequently asked questions by a beginner who has started learning Java programming language and is not aware of how to convert from one data type to another. Converting String to long is similar to converting String to Integer in Java, in-fact if you know how to convert String to Integer then you can convert String to Long by following the same procedure. Though you need to remember few things while dealing with long and String first of all long is the primitive type which is wrapped by the Long wrapper class and String is an Object in Java backed by character array.

How to Count Negative Numbers in a Sorted Matrix? [Solved] (Amazon Coding Question)

Hello guys, earlier I shared a list of Google Coding Interview questions, and today, I am going to share with you an interesting coding problem which was asked on Amazon, how to count total negative numbers in a given matrix where rows and columns are sorted in increasing order. Again, I found this coding problem while surfing on the internet, It wasn't actually asked to me or my reader, so I can't vouch that it's actually an Amazon Interview question. Though, I really expect it to be because it's an interesting problem and the optimal solution is not so easy but with the internet, you never know.

Java Program to find factorial of number in Java - Example Tutorial

How to find the factorial of a number in Java in both recursive and iterative ways is a common Java interview question mostly asked at the fresher level. It’s not just popular in Java interviews but also in other programming languages like C or C++. It's also famous  In our last article we have seen how to check if a number is prime or not and in this Java programming tutorial, we will see a simple Java program to find the factorial of a number in Java by using recursion and iteration. The same program can also be used to print factorial of any number or print a range of factorial as well.

How to check if array is a binary heap in Java? [Solved]

Problem : You have given an array of integer, check if the given array represents a binary max-heap data structure. In max heap every node is greater than all of its descendants. 

For example :

Input: array[] = {100, 25, 20, 17, 22, 12} 

Output: true

The given array represents below tree

100

/ \

25 20

/ \ /

17 22 12 

This binary tree follows max-heap property as every node is greater than all of its descendant. 

10 Code Review Checklist and Best practices in Java

What to review while doing Code review
Code Review and Unit testing are some of the best development practices I always recommend, strive for, and enforce as much as possible. Even just by doing code review and Junit test case always offer positive results it can be improved a lot by constantly learning from our mistakes, others mistakes and by observing how others are doing it. I always try to get my code review done by someone with more technical and domain experience so that I can capture any domain-specific scenarios which have been missed during think through the process.

How to find the first element in Stream in Java 8? findFirst() Example

In Java 8, you can use the Stream.findFirst() method to get the first element of Stream in Java. This is a terminal operation and is often used after applying several intermediate operations e.g. filter, mapping, flattening, etc. For example, if you have a List of String and you want to find the first String whose length is greater than 10, you can use the findFirst() method along with stream() and filter() to get that String. The stream() method gets the Stream from a List, which then allows you to apply several useful methods defined in the java.util.Stream class like filter(), map(), flatMap() etc.

10 Examples of Optional in Java 8

Null is bad, it can crash your program. Even its creator called it a billion-dollar mistake hence you should always try to avoid using nulls whenever you can. For example, you should not return a null String when you can return an empty String, similarly never return null collections when you can return an empty collection. I have shared many such tips in my earlier article, 10 tips to avoid NullPointerException and my reader liked that a lot. But, I wrote that article a couple of years ago when Java 8 was not around and there was no Optional, a new way to avoid NullPointerException in Java, but, things have changed now.

Why use SLF4J over Log4J for logging in Java? Example

Every Java programmers know that logging is critical for any Java application, especially server-side application, and many of them are already familiar with various logging libraries e.g. java.util.logging, Apache log4j, logback, but if you don't know about SLF4J, Simple logging facade for Java,  then it's time to learn and use SLF4J in your project. In this Java article, we will learn why using SLF4J is better than using log4j or java.util.logging. It’s been a long time, since I wrote 10 logging tips for Java programmer,I don’t remember anything I have writing about logging.

How to replace NULL with Empty String in SQL Server? ISNULL() vs COALESCE() Examples

We often need to replace NULL values with empty String or blank in SQL e.g. while concatenating String. In SQL Server, when you concatenate a NULL String with another non-null String the result is NULL, which means you lose the information you already have. To prevent this, you can replace NULL with empty String while concatenating. There are two ways to replace NULL with blank values in SQL Server, function ISNULL(), and COALESCE(). Both functions replace the value you provide when the argument is NULL like ISNULL(column, '') will return empty String if the column value is NULL.

5 Reasons to Use Composition over Inheritance in Java and OOP - Example

Favor composition over inheritance is one of the popular object-oriented design principles, which helps to create flexible and maintainable code in Java and other object-oriented languages. Many times I have seen people suggesting use composition instead of inheritance, in fact, my favorite books like Head First Design Patterns also advocate this design principle. The Head First books have their own way of explaining, why composition is better than inheritance, and though it's long it's quite interesting and informative. It was the first chapter of this book, which helped me a lot in understanding this key OOP concept. 

Difference between char, varchar, nchar and nvarchar data types in SQL Server? Example

What is the difference between char and varchar in SQL, followed by nchar and nvarchar, is one of the popular SQL interview questions, and surprisingly not every programmer knows this basic difference. If you go with the name, which you should, then you can figure out that char is a fixed-length data type while varchar should be a variable-length data type. Though all char, varchar, nchar, and nvarchar are used to store text or String data there are subtle differences between them. As I said char is fixed length, which means a variable or a column like Zipcode char(10) will take only 10 bytes to store data, including space.

Observer design Pattern in Java with Real world code Example

Observer design pattern in Java is a fundamental core Java pattern where Observe watches for any change in state or property of Subject. For Example, Company updates all its shareholders for any decision they make here Company is Subject and Shareholders are Observers, any change in the policy of company and the Company notifies all its Shareholders or Observer. This was a simple real-world explanation of the Observer pattern. 

What is Factory method Design Pattern in Java with Example - Tutorial

Factory design pattern in Java one of the core design pattern which is used heavily not only in JDK but also in various Open Source framework such as Spring, Struts and Apache along with decorator design pattern in Java. Factory Design pattern is based on Encapsulation object oriented concept. Factory method is used to create different object from factory often refereed as Item and it encapsulate the creation code. So instead of having object creation code on client side we encapsulate inside Factory method in Java. One of the best examples of factory pattern in Java is BorderFactory Class of Swing API.

Builder Design pattern in Java - Example Tutorial

Builder design pattern in Java is a creational pattern i.e. used to create objects, similar to factory method design pattern which is also a creational design pattern. Before learning any design pattern I suggest find out the problem a particular design pattern solves. Its been well-said necessity is a mother of invention. learning design pattern without facing problems is not that effective, Instead, if you have already faced issues then it's much easier to understand design patterns and learn how they solve the issue

How to Find Duplicate values in a Table? SQL GROUP BY and Having Example| Leetcode Solution

Hello guys, if you are wondering how to find duplicate values in a table then don't worry, there are many ways to find duplicate rows or values from a given table. For example, you can use the GROUP BY and HAVING clause in SQL with count function to find all the rows which has same values for a particular column and then filter out rows where count is just one, I mean unique values. This way you can find all the duplicate from a given table. Using group by you can create groups and if your group has more than 1 element it means it's kind of duplicate.