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ArrayList.contains(), size(), clear, asList(), subList(), toArray(), and isEmpty() Example in Java Java ArrayList Example ArrayList in Java is one of the most popular Collection classes. ArrayList is an implementation of the List interface via AbstractList abstract class and provides an ordered and an index-based way to store elements. Java ArrayList is analogous to an array, which is also index-based. In fact, ArrayList in Java is internally backed by an array, which allows them to get constant time performance for retrieving elements by index. Since an array is fixed length and you can not change their size, once created, Programmers, starts using ArrayList, when they need a dynamic way to store object, i.e. which can re-size itself. See the difference between Array and List for more differences. Java Interview questions and tutorials Read: http://www.java67.com/2013/03/java-arraylist-how-to-example-and.html

How to Read User Input and Password in Java from command line? Console Example Hello guys, if you are wondering how to take user input from command prompt in Java like username and password then don't worry. Java provides several utilities like Scanner and BufferedReader to read input from command prompt in Java. Java 6 added a new utility class for reading input data from character based devices including command line. java.io.Console can be used to read input from command line, but unfortunately, it doesn't work on most of the IDE like Eclipse and Netbeans. As per Javadoc call to System.Console() will return attached console to JVM if it has been started interactive command prompt or it will return null if JVM has been started using a background process or scheduler job. Java Interview questions and tutorials Read: http://www.java67.com/2013/05/reading-input-and-password-from-command-prompt-Console-example.html

How to replace characters and substring in Java? String.replace(), replaceAll() and replaceFirst() Example One of the common programming tasks is to replace characters or substring from a String object in Java. For example, you have a String "internet" and you want to replace the letter "i" with the letter "b", how do you that? Well, the String class in Java provides several methods to replace characters, CharSequence, and substring from a String in Java. You can call replace method on the String, where you want to replace characters and it will return a result where characters are replaced. What is the most important point to remember is that the result object would be a new String object? Java Interview questions and tutorials Read: http://www.java67.com/2013/03/how-to-replace-string-in-java-character-example.html

Where Is Python Used In The Real World? Hello guys, if you are wondering where is Python used in real world before you decide whether to learn Python programming language or not then its actually a good question. While everyone is talking about Python's popularity, it make sense to do research and find out which industries in Software development is using Python as their primary language. You will be surprised to know that like Java Python is also almost everywhere. Python is now used in Artificial Intelligence, Web Development, Game Development, Building Desktop and UI Apps, Machine Learning, Data Science, Data Analysis, Building Mobile apps, Web Scrapping, and most importantly on Automation. So, you can see that Python is widely accepted and used and learning Python is the best decision you can take to start your career as Software Developer. Java Interview questions and tutorials Read: http://www.java67.com/2022/08/where-is-python-used-in-real-world.html

How to use @PropertySource Annotation in Java and Spring? Property Source Example Hello Java developers, if you are wondering What is property source in Spring Framework and how to use @PropertySource annotation then you have come to the right place. Earlier, I have shared the best books and online courses to learn Spring Frameworkand in this article, I will teach you how to use @PropertySource annotation in Spring to read Environment variables and inject properties using @Value annotation. In the Spring application, one of the files that are needed to provide properties to the Spring environment is the @Configuration classes. Java Interview questions and tutorials Read: http://www.java67.com/2021/10/what-is-property-source-in-spring.html

Top 24 Node.js Interview Questions with Answers for 1 to 2 Years Experienced Web Developers Hello guys, if you are preparing for a JavaScript developer or web developer and looking for common Node.js questions to prepare for interviews then you are at right place. In the past, I have shared JavaScript interview questions, React Questions, Angular Questionsand even web development questionsand in this article, I am going to share frequently asked Node.js questions with answers for interviews.  Though Node.js is defined as a JavaScript environment, it is widely considered as a backend framework. Since its inception in 2008, Node.js has become a popular term in the server-side development community. More and more companies are using Node.js for backend development. Java Interview questions and tutorials Read: http://www.java67.com/2022/02/nodejs-interview-questions-with-answers.html

Difference between StringBuilder and StringBuffer in Java with Example If you are in a hurry and heading straight to interview then I won't take much of your time, In a couple of words, the main difference between StringBuffer and StringBuilder is between four parameters, synchronization, speed, thread-safety, and availability. StringBuffer is synchronized and that's why thread-safe, but StringBuilder is not synchronized, not thread-safe and that's why fast. Regarding availability, StringBuffer is available from Java 1.0 while StringBuilder was added in Java 5. Java Interview questions and tutorials Read: http://www.java67.com/2014/05/difference-between-stringbuilder-and-StringBuffer-java.html

Top Java Blogs Weekly: Best of 35/2022 Best of Top Java Blogs, year 2022, week 35 Read: https://www.topjavablogs.com/news/best-of-35-2022

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Java + Spring Boot + Microservices Example - How to create a Microservice in Java using Spring Boot? Hello guys, if you are wondering how to create a Microservice in Java and Spring Boot then you are ar the right place. In the past, I have shared best Spring Boot courses for Microservices, Interview Questionsas well as essential Microservice design principles and patternslike circuit breaker, CQRS, Event sourcing etc and In this article, we will cover the fundamentals of microservices with Spring Boot utilizing Spring cloud. We will cover a few fundamental ideas and then we will make a little micro-service to give you an outline. I will also share step by step guide to make Microservices in Java and then deploy them using Docker and Kubernetes on Cloud. Java Interview questions and tutorials Read: http://www.java67.com/2022/08/java-spring-boot-microservices-example.html

How to check if a Number is Power of Two in Java? [Bitwise AND Example] Hello guys, if you are thinking about how to check if a given number is a power of two without using an arithmetic operator like division then you have come to the right place. In Java, you can use bitwise operators like bitwise AND check if a given number if the power of two or if the given number is even or odd. In this Java Programming tutorial, you will learn how to check if the number is the Power of two using a bitwise operator. The main purpose of this program is to teach you how to use bit-wise operators like bitwise AND (&)  in Java. A number is said to be the power of two if all its prime factors are 2, but in the binary world, things work a little differently. Java Interview questions and tutorials Read: http://www.java67.com/2015/06/how-to-use-bitwise-operator-in-java.html

Top 20 Java Access Modifier Interview Questions Answers for 1 to 2 Years Experienced Access modifiers is one of the essential concept in Java and every programmer should be familiar with, and because of its importance, its also a popular topic in Java interviews. Access modifier can be applied to class, method, fields, and variables and as the name suggests they control the access. Like who can access that particular class, method or variable. For example, public modifier provides universal access which means any public class, method or variable is accessible by everyone and everywhere. In other words, you can access a public class both within the package and outside the package. Java Interview questions and tutorials Read: http://www.java67.com/2022/05/java-access-modifier-interview.html

How to convert an ArrayList to Array in Java? ArrayList of String Example Hello guys, if you are wondering how to convert an ArrayList of objects to an array of Object in Java then you have come at the right place. In this article, I will show you a couple of ways to convert an ArrayList to Array in Java. For example, you can start with creating a new array and then copying elements from ArrayList to array, or you can also use use Stream to go through all elements of ArrayList and then collect result in an array. In this example, we will use Arrays.copyOf()method to convert a given ArrayList to array in Java. This method can be used to convert any ArrayList like ArrayList of Integer, String or any custom object to Array in Java. Java Interview questions and tutorials Read: http://www.java67.com/2012/09/java-program-to-convert-string-arraylist-to-string-array.html

How to Delete Objects from ArrayList in Java? ArrayList.remove() method Example Hello guys, if you are wondering how to remove an element from a given ArrayList in Java then you are at right place. Earlier, I have shared how to sort ArrayList in Java as well how to loop over ArrayList in Java and In this Java ArrayList tutorial, you will learn how to remove elements from ArrayList in Java e.g. you can remove String from ArrayList of String or Integer from ArrayList of Integers. There are actually two methods to remove an existing element from ArrayList, first by using the remove(int index) method, which removes elements with a given index, remember the index starts with zero in ArrayList. Java Interview questions and tutorials Read: http://www.java67.com/2015/06/how-to-remove-elements-from-arraylist.html

5 Difference between Hashtable vs HashMap in Java? Answer Hashtable vs HashMap in Java Hashtable and HashMap are two hash-based collections in Java and are used to store objects as key-value pairs. Despite being hash-based and similar in functionality there is a significant difference between Hashtable and HashMap and without understanding those differences if you use Hashtable in place of HashMap then you may run into series of subtle programs which is hard to find and debug. Unlike the Difference between ArrayList and HashMap, Differences between Hashtable and HashMap are more subtle because both are similar kinds of collections. Before seeing the difference between HashMap and Hashtable let's see some common things between HashMap and Hashtable in Java. Java Interview questions and tutorials Read: http://www.java67.com/2012/08/5-difference-between-hashtable-hashmap-Java-collection.html

How to write a Parameterized Method in Java using Generics? Example Hello guys, if you are wondering how to write a parameterized method in Java using Generics then you are at right place. Earlier, I  have shared Complete Java Generics tutorial as well as popular Generics Interview Questions and in this article, I will teach you how to write a parameterized method using Generics in Java step by step. A method is called a generic method if you can pass any type of parameter to it and it will function the same like it allows the same logic to be applied to different types. It's known as a type-safe method as well. Java Interview questions and tutorials Read: http://www.java67.com/2019/09/how-to-write-generic-method-in-java.html

10 Examples of nslookup command in Linux and Windows Hello guys, if you are wondering what is nslookup command and how to use in Linux and Windows then you are at right place. In the past, I have shared examples of crontab, find, grep, netstat, and curl commandand In this article, I will share 10 different examples of nslookup command, each using its different powerful command line option to give you the tool you need to deal with networking  related queries. I often use nslookup command to convert a given IP address to hostname or a given hostname to IP address. For example, when I see an IP address in our log file and want to find which host that request is coming from, I use nslookup. Java Interview questions and tutorials Read: http://www.java67.com/2022/08/10-examples-of-nslookup-command-in.html

Difference between Polymorphism vs Inheritance in Java and Object Oriented Programming - Example Programmers often confused among different object-oriented concepts e.g. between Composition and Inheritance, between abstraction and encapsulation, and sometimes between Polymorphism and Inheritance. In this article, we will explore the third one, Polymorphism vs Inheritance. Like in the real world, Inheritance is used to define the relationship between two classes. It's similar to the Father-Son relationship. In object-oriented programming, we have a Parent class (also known as the superclass) and a Child class (also known as the subclass). Similar to the real world, a Child inherits Parents' qualities, like its attributes, methods, and code. Java Interview questions and tutorials Read: http://www.java67.com/2014/04/difference-between-polymorphism-and-Inheritance-java-oops.html

How to convert ArrayList to Comma Separated or Delimited String in Java - Spring Example Some time we need to convert ArrayList to Stringin Java programming language in order to pass that String to stored procedure, any method or any other program. Unfortunately Java collection framework doesn't provide any direct utility method to convert ArrayListto Stringin Java. But Spring framework which is famous for dependency Injection and its IOC container also provides API with common utilities like method to convert Collection to String in Java. You can convert ArrayList to String using Spring Framework's StringUtils class. StringUtils class provide three methods to convert any collection e.g. ArrayList to String in Java, as shown below: Java Interview questions and tutorials Read: http://www.java67.com/2012/10/how-to-convert-arraylist-to-string-in-java-example.html