Java is a constant contributor in the software domain, especially in software development. It is necessary to learn and master Java skills. You have to practice the skills in real-time. Here we are bringing you, the essentials to face a Java interview and the most eagerly sought-after Java Interview questions. It will help you face a Java interview and to test your skills and knowledge beforehand.
Java knowledge carries a lot of career potential. It is the major reason for the vast number of beginners and professionals in programming. According to LinkedIn, there are 1,68,000 plus Java jobs in U S A. Java Developer comes 2nd in the US in Glassdoor’s 2020 list of 50 Best Jobs.
However, the question intriguing the job seekers is, how to prepare for a Java job interview.
What is Java?
Java is a “blue-collared” language, touching every field of software development. It is the most widely used programming language in the current IT industry. You can find its applications in technical every field. Because of its high performance, robustness and security features, Java is mostly used in banking applications.
When you need to develop a secure and scalable application, you should definitely opt to go with Java. Currently, about three billion mobile phones are implemented in Java, as well as about 125 million TV sets, and each Blu-ray player use Java. Every big organization uses Java in one way or another. More than 64,000 companies are using it in the United States. Google uses Java to build and develop Google Docs applications.
Java can be used in enterprise applications, network applications, desktop applications, web applications, games, android apps, and many more. Java is also emerging as the preferred language in the trending Big data field.
The Most Important Java Applications
Java provides a lot of features that help you to develop GUI applications. Java provides AWT, Swing API or Java Foundation Classes, or the latest JavaFX, from Java 8 onwards. These APIs/features help develop advanced GUI applications, including advanced tree-based or even 3D graphical applications. Desktop tools such as Acrobat reader and ThinkFree were developed using Java.
Web Development
Java has finest features for web development and Servlets, Struts, Spring, hibernate, JSPs. Amazon, Broadleaf and Wayfair web tools use Java.
Java provides J2ME, a cross-platform framework to build mobile applications. Android is developed using Java-based Android SDK. Netflix, Tinder, Google Earth and Uber are some of the popular Java-based apps.
Most enterprise computers run Java. Enterprise Resource Planning (ERP) systems and Customer Resource Management (CRM) systems use it.
Scientific applications are developed using Java. It provides powerful mathematical calculations. Mat lab uses Java tools.
Applications of Java in real world include Project Jigsaw, Apache Tomcat, Rimfaxe Web Server (RWS). Application servers like WebSphere, JBoss, and WebLogic, are Java-based. Embedded systems like SIM cards and Blue-ray disc players use Java.
Leading financial institutions .use Java-based software tools for their business, It is used to write server-side applications that receive data from one server, processes it, and sends the processed data to the other servers or processes.IDEs like Eclipse, IntelliJ IDEA, and Net beans are all written and developed in Java.
Samsung and Nokia handsets use J2ME. It is popular with products like Cards, Blu-ray, and Set-Top Boxes. WhatsApp is available in J2ME.
Game development companies use Java, It is because, it has the support of the open-source most powerful 3D engine. The engine gives unparalleled capacity when designing 3D games. Java based popular games are Minecraft and Mission Impossible III. It is used in popular frameworks and libraries available for Game Development, like - LibGDX and OpenGL.
Java is used to develop SaaS (Software as a Service), LaaS (Logging as a Service), and PaaS (Platform as a Service). Java based Cloud applications are used to share data between companies and to develop applications remotely.
Many programming languages are useful for IoT. But for developers, Java offers an unparalleled edge over others.
Google, Printerest, Uber,Instagram, Spotify, Netflix, Airbnb, Naukri, Jabong, Myntra, Flipkart, Trivago, ibibo, TripAdvisor, TCS, Infosys, HCL, Wipro, eBay, etc. use Java. NASA Word Wind, the project of an independent agency of the U.S. federal government NASA, uses Java.
Java is used in RMI (Remote Procedure Invocation) and CORBA (Common Object Request Broker Architecture), the APIs to develop a distributed application.
Jini (Java Intelligent Networking Infrastructure) gives the infrastructure to provide, register, and find distributed services based on its specifications.
Why Java?
Java differs from other languages by its security and functional properties. It has Cross-Platform, Memory Management, Multi-threading Scalability features.
Scalability improves the capacity of the system by adding the system resources without affecting the deployment architecture. It adds capacity to your system. You can achieve scalability by increasing the resources such as RAM and CPU in a single system. it increases the performance, maximizes productivity and handles the workload.
Java has a tremendous advantage: it can be run on all platforms. It manages memory, and automatically deletes the objects when they are no longer valid. At the same time, it improves the speed.This bytecode is understood by the JVM.
Thread is a lightweight sub process. Multi-threading in Java allows concurrent execution of two or more threads simultaneously. It maximizes the utilization of the CPU.
Java applications at a glance:
Desktop GUI Applications
Mobile Applications
Enterprise Applications
Scientific Applications
Web-based Applications
Embedded Systems
Big Data Technologies
Distributed Applications
Cloud-based Applications
Web servers and Application servers
Software Tools
Gaming Applications
The Common Interview Questions
Here is a guide to help you crack the most frequently asked Java Interview questions.
What are the advantages of Java
Java is used in real life situations. It is there in E-commerce, Financial, enterprise, mobile, distributed, and big data applications.The financial software used by Citigroup, Barclays and such banks is Java-based.Google and Amazon use Java-based applications for operations.Google Docs is java based.
Most of the data processing and scientific projects are Java based. It is secure, fast, portable reliable and platform independent.
What do you understand by Object, Class, JVM, JDK and JRE?
An object is a collection of methods and classes which represent its state and do operations. A Class is a new type of data used to create objects.
Java Virtual Machine (JVM) offers a run time environment for codes.
Java Development Kit (JVK) is to write and execute a program. It contains the JRE with development tools.
Java Runtime Environment (JRE) is a collection of files for JVM during run time.
What is looping?
Loops are used to execute a certain statement repeatedly or block of statements.
There are three types- For Loops, While Loops and Do While Loops.
What is Overloading and Overriding?
When there are two methods of same name, having different properties, it is a case of Overloading. Overriding refers to two methods with the same name and properties but the two occurring in a parent and child class respectively.
What is WORA?
Write Once Read Anywhere is the property of a language that enables it to run on any platform. It is midway between machine code and source code and is not platform specific.
Wish you all success in the interview!
© Ramachandran
