How to find first recurring character in given String? [Solved] [Google Interview Coding Problem]

Hello guys, while surfing the Internet for a couple of weeks back, I come to know that this problem was asked on Google interviews, find the first recurring character in a given String. I don't know if that's true but this looks like a very simple coding problem from Google's Interview standard. If it was indeed asked, then that guy must have been very lucky. Anyway, I liked this coding problem and thought to write about it, becuase it's a good coding problem to check candidates' data structure and algorithms skills because it's tricky. It's tricky because it's very easy to make a mistake assuming just one recurring character in String, which you should avoid.

Top 5 Online Courses to learn Tableau in 2021 - Best of Lot

In the era of Big Data and Data Science, Data Visualization and Analytics have become very important. Data visualizations like dashboards and charts help you to better understand the data and provide you insights. They also help simplify complex data sets into concise images and diagrams that clients and users can easily digest. What would you do with the data if you cannot analyze it to gain insights which can help with your business growth and some path-breaking discoveries and that's where Data Visualization and Analytics tools like Tableau play an essential role. 

How to use Callable and Future in Java? Example Tutorial

A callable interface was added in Java 5 to complement the existing Runnable interface, which is used to wrap a task and pass it to a Thread or thread pool for asynchronous execution. Callable actually represents an asynchronous computation, whose value is available via a Future object. All the code which needs to be executed asynchronously goes into the call() method. Callable is also a single abstract method type (SAM type), so it can be used along with lambda expression on Java 8. Both Callable and Future are parametric types and can be used to wrap classes like Integer, String, or anything else.

How to use wait, notify and notifyAll in Java - Producer Consumer Example

You can use wait, notify, and notifyAll methods to communicate between threads in Java. For example, if you have two threads running in your programs like Producer and Consumer then the producer thread can communicate to the consumer that it can start consuming now because there are items to consume in the queue. Similarly, a consumer thread can tell the producer that it can also start putting items now because there is some space in the queue, which is created as a result of consumption. A thread can use the wait() method to pause and do nothing depending upon some condition. For example, in the producer-consumer problem, the producer thread should wait if the queue is full and the consumer thread should wait if the queue is empty.

Top 5 Course to learn Splunk for Beginners in 2021 - Best of Lot

Hello guys, if you want to learn Splunk, one of the most popular tools for aggregating, monitoring, and visualizing data, particularly logs files then you have come to the right place. In the past, I have shared the best courses to learn DevOps, Selenium, and Machine Learning and in this article, I am going to share the best online courses to learn Splunk for Beginners and Experienced programmers. I first come to know about Splunk in one of the company workshops where they are switching to Splunk for better monitoring of log files. I really like the concept of installing Splunk agent on boxes and then seeing logs from all production machines in one place in a web-based interface. 

Udemy vs Pluralsight Review 2021 - Which is better to Learn to Code and Programming?

Hello guys, how are you doing? I am again back with answering one of the familiar doubts among online learners, Pluralsight, or Udemy? Which are the better websites for learning code and leveling up your programming skills? As a Java blogger and editor of a Medium publication, I often receive questions like this from my readers. Earlier I have answered questions like Pluralsight vs. CodeCademy and Udemy vs. CodeCademy but never explained about Pluralsight vs. Udemy, which many of my readers have been asking for a long time. Since Pluralsight and Udemy are two of the most popular online learning platforms and I also spend considerable time every day on each of them, I felt to write my review of Udemy and Pluralsight and explain the pros and cons of both Udemy and Pluralsight so that you can make an informed decision when it comes to learning tech skills online.

Top 10 Advanced Core Java Courses for Experienced Programmers in 2021 - Best of Lot

Hello guys, Many of my readers have been asking me for advanced Java courses to improve topics like Java collections, Stream API, Design Patterns, Concurrency, Java Performance, Generics, Garbage Collections, and new features introduced in recent Java releases like Java Modules System. If you also had that question in mind and looking for some great courses to learn core Java in-depth, then you have come to the right place. In this article, I will share some of the advanced core Java courses for experienced programmers. These courses you should take to truly master Java programming concepts, tools, libraries and become a Java expert that every company wants to hire, massive investment banks.

Top 5 courses to prepare for Data Science and Machine Learning interviews in 2021 - Best of Lot

Hello guys, if you are preparing for Data Science or Machine Learning interviews and looking for best resources for preparation then you have come to the right place. Earlier, I have shared best coding interview courses and algorithms courses and in this article, I Am going to share best online courses you can join to prepare for Data Science and Machine Learning interviews. Data science and machine learning are two developing technologies. Today in 2020, there is a huge job market for those individuals who are well-acknowledged in data science and machine learning. But these two technologies are complex and require a lot of effort and time. 

Top 5 Courses to learn Java Collections and Stream API in 2021 - Best of Lot

Hello guys, If you have been programming in Java, then you know that Collections and Streams are two of the most important Java APIs. There is hardly any Java program I have written in my 15 years of professional Java development career where I have not used any classes from Collections and recently from Stream API. I strongly believe that every Java developer should have a good knowledge of both of them, and that's why I am writing this post. If you are new to Java, then you might be thinking about why they are so important? Well, they are important becuase they deal with data, and data is at the heart of every application and business. For example, if you create an application like Facebook, then where do you store your Users on memory?

[Review] - Is Grammarly Worth it in 2021? A Grammarly Review for Bloggers and Writers [UPDATED]

Hello guys, today, I am going to share my review of Grammarly - one of the powerful writing tools for bloggers, programmers, writers, students, and anyone who wants to write correct English without grammatical and spelling mistakes. I have regularly been blogging since 2010 and have written more than 1000 articles on Java, Programming, and Technology, but didn't talk much about blogging itself. After many requests from my readers for blogging tips, my experience, and what should a programmer do for his improvement and financial stability, I have decided to write occasional posts about my blogging experience, and this one is the first on that series. 

Top 5 Spring Microservices Courses with Spring Boot and Spring Cloud in 2021 - Best of Lot

Microservices is the new buzzword in software development word and everybody is talking about it, but it's been in practice for quite some time especially in the form of RESTful web services. The idea of Microservices is simple, breaking a big monolithic application that contains everything from UI to service layer to database into small chunks of applications that are loosely coupled and can work on their own. For example, in a company like Uber, you could have several applications providing different services e.g. discovering when a driver is online or a passenger is searching for a cab, finding a route, traffic, and handling payments. These small applications are known as Microservices.

How to implement Bucket Sort in Java? [Solved] - Example Tutorial

In recent years, one of the questions I have increasingly seen in programming job interviews is about constant time sorting algorithms like do you know any O(n) sorting algorithm? how do they work? When I first encountered this question, I had no idea whether we can sort in constant time because even some of the fastest sorting algorithms like QuickSort or MergeSort take O(N log N) time for sorting on their average case. After some research, mainly by going through the classic CLRS book and this DS and Algorithms course by Tim Buchalka and Goran Lochert on Udemy, I come to know that there indeed are some constant time or linear time sorting algorithms like bucket sort, counting sort, and radix sort, which can sort an array in O(n) time but they work with only a special set of input.

Top 5 Java Multithreading and Concurrency Courses for Experienced Programmers in 2021 - 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 Courses to Prepare for Frontend Interviews in 2021 - Best of Lot

Hello guys, if you are preparing for a frontend developer interview and looking for the best interview preparation resources like online courses, books, and tutorials then you have come to the right place. Earlier, I have shared the best coding interview preparation courses, and  books, and in this article, I am going to share the best  Frontend developer interview courses. Web development is generally divided into two parts - frontend (client-side) development and backend (server-side) development. A web developer can either be a master in front-end development or backend development. 

Top 5 Apache Kafka Courses to learn Online in 2021 - Best of Lot

Hello guys, you might have heard about Apache Kafka, the next generation, Big Data messaging system which is handling billions of messages per day on companies like LinkedIn, Uber, Airbnb, Twitter, etc. It's a revolutionary technology and perfect for today's mission-critical application which has so much data to process and analyze. Since last year, I have been sharing a lot of resources like books, courses, and tutorials to learn these sunrise technologies so that you can aware of these and learn them to make yourself more valuable or jump into some exciting career path. For example, In the past, I have shared some awesome courses on Big Data, Spark, and Hadoop and many of my readers requested me to share similar suggestions for Apache Kafka.

2 Best Open source Java Libraries to Create PDF documents - iText vs Apache FOP

PDF format is a popular format for sending receipts, email confirmation, and other documentation and we often have a requirement to create PDF documents using Java, mostly in JSP pages. Since most of the official documentation uses PDF format nowadays, it becomes imperative to support PDF files. Recently I received a couple of questions regarding the suggestion of open-source Java PDF libraries, like which is the best open source PDF library in Java or should I use iText or Apache FOP in my Java application for PDF processing. These questions motivates me to write this post. In this article, I will share a couple of Java based open source PDF libraries, both FREE and with some licensing fees, which you can use to generate PDF documents in Java projects.

How to check for Null in SQL Query? IS NULL Example Tutorial

One of the most common SQL Interview questions on Programming interviews is to select some rows from a table that also contains null values. Since many SQL developers are used to using = and != operator on WHERE clause, they often tend to forget the fact that column allows NULL or not. Using = or != is perfectly fine if your column has NOT NULL constraint and you know for sure that there are no NULL values in that column, but it does contain NULLs then your SQL query will return the incorrect result at times. This is one of the most common mistakes but at the same time hard to find SQL bugs if it managed to get into the real environment. In this article, you will learn the right way to check NULL values in SQL queries using IS NULL and IS NOT NULL predicates.

Top 5 Courses to learn Quarkus, MicroNaut, DropWizard, and Vert for Java Microservices in 2021 - Best

Hello guys, if you create Microservices in Java and want to explore frameworks like DropWizard, MicroNaut, and Quarkus, you have come to the right place. In the past, I have shared the best Microsercies courses with Spring Boot and Spring Cloud, and today, I will share the best online lessons to learn Dropwizard and Micronauts. These are the best online courses and tutorials you can get to know this helpful technology. Unfortunately, not many online courses are available, but API docs and guides are also handy; along with these courses, you can read them.

What is difference between ArrayList and ArrayList<?> in Java?- Raw Type vs Wildcard Example Tutorial

One of my readers asked me about the difference between ArrayList vs ArrayList< in Java?>, which was actually asked to him in a recent Java development interview. The key difference between them is that ArrayList is not using Generics while ArrayList is a generic ArrayList but they look very similar. If a method accepts ArrayList or ArrayList<?> as a parameter then it can accept any type of ArrayList like ArrayList of String, Integer, Date, or Object, but if you look closely you will find that one is raw type while the other is using an unbounded wildcard. What difference that could make? Well, that makes a significant difference because ArrayList with raw type is not type-safe but ArrayList<?> with the unbounded wildcard is type-safe.

Top 12 Hibernate Interview Questions and Answers for Java Developers [Solved]

Hibernate Interview Questions are asked on Java J2EE Interviews, mostly for web-based enterprise application development roles. The success and acceptability of Hibernate framework on the Java world have made it one of the most popular Objects Relational Mapping (ORM) solutions in the Java technology stack. Hibernate frees you from database-specific coding and allows you to focus more on utilizing powerful object-oriented design principles to implement core business logic. By using Hibernate you can switch between databases rather easily and also take advantage of out-of-box caching facilities provided by Hibernate, in terms of second-level cache and query cache.

Top 5 Project-Based Courses to learn Coding with Java, Python, and JavaScript in 2021 - Best of Lot

Hello guys, if you are aiming to learn programming and code in 2021 with Java, Python, or JavaScript, the top 3 programming languages of the world then I suggest you join a project-based course. These are the courses where you will learn things by doing and I think that's the best way to learn programming and coding. Reading a book is Ok, watching videos are also Ok but they will not make you a Programmer or Coder, you must code to become a coder and these project-based courses give you that opportunity.

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.

Top 5 Online Courses To Learn Computer Security in 2021 - Best of Lot

Computer security is a complex field of learning but must for everybody learn to protect themselves and their companies from letting bad people access your sensitive information they shouldn’t access. We always hear in the newspaper how evil people harm companies and people and make the world lose billions of dollars every year. It looks like bad people are winning the battle against giant companies and beginner people in security. Still, you can change that by taking some courses that will teach you at least the basics of computer and network security and how these guys can access your computer and information using many techniques such as social engineering and stopping them.

Top 21 Tech Skills Java Developers Can Learn in 2021

Hello guys, recently I was doing some research on what skills Java developers should learn in 2021 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.

Top 5 React and Redux Courses to Learn Online in 2021 - 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.