Sunday, March 24, 2019

How to Crack Java Programming Interviews in 2019? Topics, Courses, Books, and Questions

Java Interviews are a little bit different than traditional programming interviews on tech giants and product based companies like Google, Amazon, Microsoft, or Facebook. First, even though it has questions from Data Structure and Algorithms like String or Array, you can still manage to clear Java interviews if you are not an expert on them. The questions are a little bit easier and more practical than those companies. Another very important thing about Java interviews are questions based upon Java programming language and JDK API. Since Java is also an Object-oriented programming language, you will find lots of OOP questions there.

2 Ways to Check if a String is Rotation of Other in Java - Algorithms

Write a program to check if one String is a rotation of another String is a common coding problem you will find on programming job interviews.  A String is said to be a rotation of another String, if it has the same length, contains the same characters, and they were rotated around one of the characters. For example,  String"bcda" is a rotation of "abcd" but "bdca" is not a rotation of String "abcd". One of the simplest solutions to this interesting problem is first to check if two String has the same length, if not then one String cannot be the rotation of another. If they are of the same length then just create another String by concatenating first String with itself, now check if second String is a substring of this concatenated String or not, if yes, the second String is a rotation of first.

Saturday, March 23, 2019

10 Unit Testing and Integration Tools and Libraries for Java Developers

In last a couple of weeks, I have written some articles about what Java developer should learn in 2019 e.g. programming languages, libraries, and frameworks, but if you have just one thing to improve or learn then that must be your automation testing skills. Testing is one of the disciplines which separates professional developers with amateur ones. It's not about following TDD, BDD, or whatever testing methodologies but at the very minimum level, you must write code to test your code automatically. Many Java developers write unit tests and integration tests which automatically run during build time, mostly by using continuous integration tools like Jenkins or TeamCity.

Difference between Stable and Unstable Sorting Algorithm - MergeSort vs QuickSort

Recently in one on the interview, after some initial questions about sorting algorithms e.g. how do you write QuickSort or difference between QuickSort and MergeSort, the interviewer asked about do you understand the difference between stable and unstable sorting algorithm? This question was new to my reader, so he says, Sorry, never heard about that. The story ended there, and Interviewer moved on to next question but like many of us, my reader went on to find more about unanswered questions and ultimately he asks me what is the meaning of a stable and unstable sorting algorithm? Some of you might be heard about it and many of you might not know about this distinction, I'll try to answer this question in this article.

Friday, March 22, 2019

Top 30 Eclipse Keyboard Shortcuts for Java Programmers

This tutorial is about 30 Eclipse keyboard shortcuts, this list is by no means complete and I will suggest you guys share eclipse shortcuts listed other than here to make this more useful. Eclipse is the most used Java development IDE and knowing these Eclipse shortcuts not only improve your productivity but also makes you more efficient. You will have more time for things you like to do. Using keyboard shortcuts also helps to impress colleagues and shows that you have a good hold on tools you used for Java Development. If you are a Java developer, who use Eclipse as your main IDE for all-purpose e.g. coding, development, and debugging, then I also suggest you take a look at Beginners Eclipse Java IDE Training Course, one of the best course to learn how to use Eclipse effectively from Java programmer's perspective.

How to Find Multiple Missing Integers in Given Array of Numbers with Duplicates in Java?

It's been a long time since I have discussed any coding or algorithm interview questions, so I thought to revisit one of the most popular array based coding problem of finding missing numbers in a given array of integers. You might have heard or seen this problem before on your programming job interviews and you might already know how to solve this problem. But, there are a lot of different versions of this problem with increasing difficulty levels which interviewers normally use to confuse candidate and further test their ability to adapt to frequent changes. In the past I have demonstrated how to find the missing number in a sorted array as well on the unsorted integer array in Java using BitSet (see here), but, with just one missing number and without any duplicates, which kinda make those problems a bit easier.