How to use filter + map + collect + Stream in Java? Example Tutorial

Hello guys, many of my readers emailed me to write a post about the map and filter function of Java 8 because they found it difficult to understand and use. Even though I have previously blogged about both map() and filter(), I am writing this post again to explain the concept in more layman's language for a better understanding of my readers and fellow Java developers. The map() function is a method in Stream class that represents a functional programming concept. In simple words, the map() is used to transform one object into another by applying a function. That's the reason the Stream.map(Function mapper) takes a function as an argument. For example, by using map() function, you can convert a list of String into List of Integer by applying Integer.valueOf() method to each String on the input list.

Top 50 SQL and Database Phone Interview Questions Answers

Database and SQL is a very important skill, not just for DBA or Database admins but also for any application developer like Java, .NET, or Web developers. This is why you would often see questions from SQL and Database in Programming interviews. For DBAs, SQL is more important than a programmer, because it being their primary skill, they are also expected to know more than a common Java or .NET developer. Since no Java interview is just about Java questions, many times I receive a request from my reader about SQL questions like how to solve a particular query or some tricky questions based upon database indexes.

How to use Environment Variables in Spring Boot's application.properties file? Example Tutorial

How to use environment variable in Spring boot's application.properties is a major problem when your spring boot application running on different places like local, Jenkins, and OpenShift. So we need to make the data source file dynamic in the application.properties file. So let's have look at how to do this at how to use the env variable in Spring Boot's application.properties. So in this tutorial, We assume that you have knowledge of Spring boot and not going to talk about small details. 

How to Create a thread-safe ConcurrentHashSet in Java 8? [Example]

Until JDK 8, there was no way to create a large, thread-safe, ConcurrentHashSet in Java. The java.util.concurrent package doesn't even have a class called ConcurrentHashSet, but from JDK 8 onwards, you can use the newly added keySet(default value) and newKeySet() methods to create a ConcurrentHashSet backed by ConcurrentHashMap in Java. This is better than old tactical solutions like using a concurrent hash map with dummy value or using the set view of the map, where you cannot add new elements. The Set returned by keySet(defaultValue) and newKeySet() methods of JDK 8 is a proper set, where you can also add new elements along with performing other set operations like contains(), remove() etc.

Why use Cloud Computing? Advantages and Disadvantages

Hello guys, If you are curious about Cloud computing and why every company, both big and small, is going to be cloud-native, you have come to the right place. In the past, I have shared the best Cloud Computing courses and both free and paid courses to learn about popular cloud platforms like AWS, GCP, and Azure. In this article, I am going back to basics and telling you about what is cloud computing and what benefits it offers. Cloud Computing has been a buzzword in the IT world for the last few years. When it first appeared, like many things, a lot of people has dismissed it as being the next big thing, but cloud computing has certainly lived up to expectations and truly shifted how the Information technology arm of business functions today.

Does Udemy, Coursera, edX, and Udacity Course Certifications Helps in Job & Career?

While online courses provide an excellent platform for learning at low cost, at your schedule, and at your own pace, I often received questions from my readers about the worth of their certifications. Many people asked me whether course completion certificates offered by Udemy, Coursera, edX, Educative, Udacity, or any such online platforms are worth any? The answer to this question is both Yes, and No because it totally depends upon what worth means for you?  If you are thinking that just completing a  Computer Science or Data Science course on Coursera and displaying a certificate on your resume or on LinkedIn will land you a job, then definitely, it's not worth it, but at the same time, these certifications can put your resume forward to many Recruiters looking for Data Scientist.