How to Swap Two Numbers Without Temp or Third Variable in Java - Interview Question Example

How to swap two numbers without using temp or third variable is a common interview question not just on Java interviews but also on C and C++ interviews. It is also a good programming question for freshers. This question was asked to me long back and didn't have any idea about how to approach this question without using temp or third variable, maybe lack of knowledge on bitwise operators in Java or maybe it didn't click at that time. Given some time and trial error, I eventually come out with a solution with just an arithmetic operator but the interviewer kept asking about other approaches of swapping two variables without using temp or third variable.

How to Print a left triangle star pattern in Java? Example Tutorial

Pattern based exercises are very common on Interviews as they are tricky for beginners and also offers coding practice. In the past, I have shared article on how to print pyramid pattern of stars in Java and Pyramid pattern of albhabets, and in this article, I will show you how to print left triangle star pattern in Java. There are different ways of printing different patterns, but most of them involves using loops and print methods like print() and println() to print characters like star, alphabets or numbers. If you know how to use loops and when to break from loop then you can easily solve pattern based coding problems. In this section, we shall be writing a program to print a left triangle star pattern. We would first implement that before I explain other things that you need to know in getting this task done.

Difference between Direct, Non Direct and Mapped ByteBuffer in Java?

ByteBuffer is one of the important classes of Java NIO API. It was introduced in java.nio package on JDK 1.4, it not only allows you to operate on heap byte arrays but also with direct memory, which resides outside the JVM. There are mainly three types of ByteBuffer in Java - Direct Byte Buffer, Non-Direct ByteBuffer, and mapped byte buffers. You can create both direct and non-direct buffers using java.nio.ByteBuffer class, while MappedByteBuffer is a subclass of ByteBuffer, which is created by FileChannel.map() method, to operate on memory-mapped file. 

How to Find Largest and Smallest of N numbers without using Array in Java? Example

One of the common programming questions is, how do you find the largest and smallest number in N numbers without using arrays in Java? Can you write a program to solve this problem? Well, it's very similar to the problem we have seen before, find the largest and smallest of 3 integers. You can use the same approach and generalize it for N numbers. All you need to do is start with largest as Integer.MIN_VALUE and smallest number as Integer.MAX_VALUE and loop through N numbers. At each iteration, compare the number with the largest and smallest number, if the current number is larger than the largest then it's a new largest, and if the current number is smaller than the smallest then it's a new smallest number.

How to Remove Duplicate Characters from String in Java? Example

This week's coding exercise is to remove duplicate characters from String in Java. For example, if the given String is "aaaaaa" then the output should be "a", because the rest of the "a" are duplicates. Similarly, if the input is "abcd" then the output should also be "abcd" because there is no duplicate character in this String.  By the way, you can not use any third-party library or Java API method to solve this problem, you need to develop your own logic or algorithm and then write code to implement that algorithm. This is one of the interesting problems from Java coding interviews and you can use this program to weed out Java programmers who cannot write code.

Difference between ByteBuffer vs byte array in Java

There are several differences between a byte array and ByteBuffer class in Java, but the most important of them is that bytes from byte array always reside in Java heap space, but bytes in a ByteBuffer may potentially reside outside of the Java heap in case of direct byte buffer and memory mapped files. Buffer is a byte array like abstraction which was introduced in Java NIO release to read and write data from FileChannel. It is extensively used in Java NIO for transferring data from one place to another and its also an essential Java concepts to know for any backend developer, particularly those who wants to create non-blocking server application using NIO in Java. 

The 2022 Laravel Developer RoadMap

Hello folks, if you want to learn Laravel for Web Development but no idea from where to start it then you have come to the right place. Laravel is one of the top PHP Framework for web development and also quite popular one. In the past, I have shared best Laravel Courses and best PHP courses and in this article, I am going to share the full 2022 Laravel RoadMap. I love these roadmap and in the past have shared many of them which you can find at the end of these article. They are often the most comprehensive guide to learn a new technology. 

How to Reverse a String in place in Java - Example

It's possible to reverse a String in place by using a StringBuilder. Since String is Immutable in Java, it's not possible to reverse the same String, but you can minimize the number of intermediate String objects by using StringBuilder or StringBuffer, which are mutable. The algorithm to reverse the String in place is similar to the algorithm we have used earlier to reverse an array in place. You need to traverse the String from one end, swapping characters at another end until you reach the middle of the String. At the point characters in your String are reversed. This algorithm only requires one extra character of memory to facilitate the swapping of characters. The time complexity of this algorithm is O(n/2)I mean O(n) where n is the length of String.

How to create an Array of Prime numbers in Java [ Sieve of Eratosthenes Algorithm Example]

Hello guys, I have said many times that a good knowledge of Data Structure and Algorithms is the first step towards becoming a better programmer and that's why I share a lot of Data structure and Algorithm stuff in this blog. To continue the tradition, I am going to share an interesting algorithm today, The Sieve of Eratosthenes algorithm, which can be used to generate prime numbers up to a given number. There are many occasions when you need to generate all prime numbers up to a specified integer and one algorithm which is most often used to generate prime numbers is the Sieve of Eratosthenes Algorithm. Surprisingly, not many developers know about this algorithm, particularly Java programmers, which is mainly because of not doing enough competitive programming.

Top 20 Kubernetes Interview Questions with Answers

Hello guys, if you are preparing for DevOps Engineer interview or a Developer interview, knowledge of Kubernetes is very important given the rise of Cloud computing and cloud native development. If you are looking for frequently asked Kubernetes interview questions to quickly revise key Kubernetes concepts then you have come to the right place. Earlier, I have shared 20 Docker Interview Questions and in this article, I am going to share frequently asked Kubernetes Interview questions with Answers. But, before we get to the 20 most important Kubernetes interview questions, let me tell you more about Kubernetes. In the most simple terms, Kubernetes is actually a bundle of software solutions that allow developers and engineers to scale and service server setups.

The 2022 Data Analyst Roadmap

Hello guys, if you are want to become a Data Analyst but not sure which skills you need and how to acquire those skills then you have come to the right place. Earlier, I have shared Java Developer RoadMap, Python Developer RoadMap, Web Developer RoadMap, iOS Developer RoadMap, and  DevOps Engineer RoadMap, and in this article, I will share Data Analyst RoadMap which will help you to become a Data Analyst in 2022. All companies have data about their customers to improve their service and get valuable insight and a much better understanding of the customer's behavior. This can be done by hiring data analysts in your company to leverage the benefits of this hug customers' data.

[Solved] Fibonacci Series in Java using Recursion and Iteration - Example Tutorial

Printing Fibonacci Series In Java or writing a program to generate Fibonacci number is one of the interesting coding problems, used to teach college kids recursion, an important concept where function calls itself. It is also used a lot as coding problems while interviewing graduate programmers, as it presents lots of interesting follow-up questions as well. In the Fibonacci series, the next number is equal to the sum of the previous two numbers. First two numbers of series are always 1 and 1, third number becomes 1 + 1 = 2, subsequently fourth number becomes 2 + 1 = 3. So a Fibonacci series looks like 1, 1, 2, 3, 5, 8, 11, 19, and so on, as shown in the image as well.

Top 20 Docker Container Interview Questions Answers for Programmers and DevOps

Hello guys, if you are preparing for Software developer job interviews like Java developer then preparing Docker is a good idea. Docker has become an essential tool and you can expect a couple of questions about Docker during Interview to check your knowledge. Having absolutely no idea of Docker before going into interview can be detrimental to your prospect considering the importance of container on deploying apps and services on Cloud. That's why I always suggest my students to prepare Docker interview questions and revise key Docker concepts before interview. If you are wondering where you can find Docker interview questions then don't worry, in this article, I have shared common Docker related questions you can prepare for interviews. They are also great to revise key Docker concepts and they cover essential areas. 

Top 12 SQL Query Questions from Interviews for Practice with Solutions

SQL, a short form of Structured Query Language is one of the essential skills in today's programming world. No matter whether you are a Java developer, C++ developer or Python developer, you must know how to write SQL queries. Every programming job interview has at least one or two questions that require you to write SQL queries for a given requirement and many developers struggle there. It's easy to answer theoretical questions like what is the difference between clustered and non-clustered index (see) or what is the difference between correlated and non-correlated subqueries (see), but when it comes time to actually write SQL queries to solve problems, it's not that easy, especially if you haven't done your homework and practice.

Quicksort Sorting Algorithm in Java - Example and Explanation

Quicksort algorithm is one of the most used sorting algorithms, especially to sort the large lists, and most of the programming languages, libraries have implemented it in one or another way. In Java, Arrays.sort() method sorts primitive data types using a double-pivot Quicksort algorithm, authored by Joshua Bloch and others. This implementation provides better performance for a lot of data sets, where traditional quicksort algorithms reduced into quadratic performance. This method also uses MergeSort, another good sorting algorithm, to sort objects. Quicksort implementations are also available in the C++ STL library.

10 Essential Skills For Cyber Security Professionals to Learn in 2022

Hello guys, if you want to become a Cyber Security Professional but not sure which skills you should learn to start your Cyber Security career then you have come to the right place. Earlier, I have shared essentials skills for Java Developers, Python Developers, app developers, and Data Analyst and in this article, I will share important skills for Cyber Security Professionals. Cyber Security is one of the most lucrative career in today's age where every company and service is going online. Most companies infrastructure are connected to the internet, such as the employee's computers and the servers where the company has their valuable and confidential data, which means it can be hacked by people outside their network and cause significant damage to their system and even reputation so they need to hire cyber security professionals to help them secure their network. 

[Solved] How to Implement Binary Search in Java without Recursion? Iterative Algorithm Example Tutorial

Hey Java programmers, if you want to implement a binary search in Java, and looking for both iterative and recursive binary search algorithms then you have come to the right place. Earlier, I have shared the free courses to learn Data Structure and algorithms in Java, and today, I am going to teach you an important algorithm.  In computer science, a binary search or half-interval search is a divide and conquer algorithm which locates the position of an item in a sorted array. Binary search works by comparing an input value to the middle element of the array. The comparison determines whether the element equals the input, less than the input or greater. 

The 2022 Python Developer Roadmap

Hello guys, if you want to become a Python developer and looking for a complete 2022 Python Developer RoadMap then you have come to the right place. In the past, I have shared Java Developer RoadMap, Web Developer RoadMap, iOS Developer RoadMap, Data Analyst RoadMap, and even a DevOps Engineer RoadMap and in this article, I am going to share with you the Python Developer RoadMap. Before writing this article, I looked for various roadmaps available online which list a lot of things you need to learn to become a Python Developer, which is really not needed. You may need them if you want to become a Python expert which can take years but just to start your career with Python, you don't need them at all.

[Solved] How to find the 3rd (kth) Node from end or tail in linked list in Java? Fast and Slow Pointer Pattern Example

Hello guys, the problem to find the 3rd element from the end in a singly linked list or Kth node from the tail is one of the tricky but frequently asked linked list problems in Programming job interviews. I know you can easily solve this problem by moving from tail to head or in the reverse direction but the main challenge here is to solve the problem in just one pass. That means, you can not traverse the linked list again and you cannot traverse backward because it's a singly linked list. So what do you think? Isn't this problem challenging? Well, I did struggle when I saw this problem very first time but once you understand the logic and some tricks to solve a linked list based problem like Recursion then it would be easy for you, and that's what you will learn in this article.

10 Essential Skills For Data Analyst in 2022

Hello guys, if you want to become a Data Analyst in 2022 but not sure which skills you need to succeed in this field or become a successful Data Analyst then you have come to the right place. In the past, I have shared essentials skills for Java developers and Python developers in 2022 and today I will share with you which skills you need to become a Data Analyst in 2022. Data analysis is a job in demand by most companies in the world who want to leverage the benefits of their data and make better decisions but analyzing data is not just knowing how to use a simple analysis software such as the Excel spreadsheet or visualize the data. It has many other skills you need to call yourself a data analyst.

[Solved] How to reverse an ArrayList in place in Java? Example

You can reverse an ArrayList in place in Java by using the same algorithm we have used to reverse an array in place in Java. If you have already solved that problem then It's a no-brainer because ArrayList is nothing but a dynamic array, which can resize itself. All elements of an array are stored in the internal array itself. By the way, if you need to reverse an ArrayList then you should be using the Collections.reverse() method provided by the Java Collection framework. It's a generic method, so you can not only reverse an ArrayList but also Vector, LinkedList, CopyOnWriteArrayList, or any other List implementation.

2 Ways to Check if a String is Rotation of Other in Java? Example

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.

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

Hello guys, 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 problems 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 candidates and further test their ability to adapt to frequent changes, which is key to surviving in the ever-changing software development world.

50 Free Spring Professional Certification Practice Questions with Answers [VMWARE EDU-1202 Exam]

Hello guys, preparing for IT certification like Oracle's Java certification or Vmware's Spring Certification required a lot of hard-work. I have seen many experienced Java developers failing these certifications and losing money and time due to over-confidence and lack of preparation. A structured preparation involves reading books, joining course and doing practice questions. When it comes to Spring certification, practice questions are quite hard to find and that's why I created my Udemy course with 250+ Spring Certification questions. This course has helped more than 9000 students in their Spring certification preparation journey. 

The 2022 iOS App Developer RoadMap

Hello guys, if you want to become an iOS App developer and looking for a solid roadmap then you are not alone. I was also looking for iOS app developer roadmap when I stumbled upon this awesome looking iOS developer RoadMap on Reddit. This is one of the comprehensive roadmap to take your from zero to master in iOS App Development but its also too much comprehensive and hard to follow. To be honest, I cannot learn all the skills mentioned in this RoadMap unless I spend all of my time on learning them for another 5 to 10 years. So, I created a simplified version of my own iOS developer RoadMap where you only need to learn essential skills to start doing iOS Development and start your career as iOS App developer.