How To Learn Java as a Beginner in 2021
Table of Contents
Java is among the top programming languages of 2020. Java is a robust, statically typed, safe, class-based programming language that has been ruling the web for some time. Java is used in almost all domains like retail, finance, healthcare, logistics, etc. It is compatible and versatile and used for mobile, desktop, and web applications, games, web servers, application servers, database connection, client-side validations, and many more. The product is free, and open-source adds to its popularity. Also, most graduates learn about C/C++ as part of their curriculum, so learning Java becomes easy.
Why Should You Learn Java?
Before you know how to learn Java, you should be convinced about why you should learn it!
Learning Java has a lot of advantages when compared to other languages. You can perform any task in Java as there are rich libraries and plugins. Java is platform-independent at the source-code and binary levels, which means the code you compile once can be used anywhere. Since Java is object-oriented, the code is split into independent modules, making the code reusable and free from bugs.
Java has a lot of security features and cross-platform capabilities. It is also the right choice for data science and machine learning, of course, after Python and R. Many websites and web applications continue to be built on the Java platform, thus keeping the demand for Java developers and designers always on the higher side. As per PayScale, a developer's average salary range is $47,169 to $106,610 per year. San Francisco and Arlington pay the highest salaries to their Java developers with about $97000 per year on an average.
If you learn Java, it also becomes easier for you to learn any other OOP based programming language in less time.
To learn Java, you must have a little idea about computer science. Java can be your first programming language to learn, but you should first be familiar with the following computer science concepts:
Since Java is an Object-Oriented Programming language (OOP), you need to know about polymorphism, inheritance, abstraction, encapsulation, and other OOP concepts. Learn more about OOP concepts.
Data Structures and Algorithms
A data structure is an assembly of data values that are organized, managed, and stored in a particular format. It also defines relationships between data values so that the values can be easily manipulated.
Java uses a lot of collection objects to organize and store data in different ways. For example, a simple list can store some integers, or names of students, or complete set of information that define a person using objects:
List<String> myList = new ArrayList<String>();
This will give the output as [James, Shane, Abby].
Similarly, algorithms like Binary search, merge sort, bubble sort, etc., are widespread, and you should be familiar with them to know the internal workings of Java collections.
Learn through the most upvoted data structures and algorithms tutorials and courses.
How to Set up the Environment
To set up Java in your machine, install JDK or Java Development Kit and JRE, i.e., Java Runtime Engine. You should have the required system memory space to install both. Both JDK and JRE can be downloaded from the Oracle website for any platform (Windows, macOS, Linux, etc.). It is simple to follow the instructions on the screen for installation; it is very straightforward. After installation, you have to set up the environment variables (PATH) on your machine. The path is nothing but the location where JDK and JRE have been installed (most likely C:\Program Files).
IDE (Integrated Development Environment)
For easy development, build, and testing purposes, it is best to use IDE to concentrate on the coding aspect more. IDE helps you follow best practices in the code, prompts for compilation (and sometimes runtime) errors, gives suggestions, generates standard code, adds comments, and more. It is also easier to import and include libraries in your workspace when you use IDE. Some popular Java IDEs are:
- Eclipse: Eclipse is a complete package for Java and J2EE development. You can add as many libraries and plug-ins as you want, and even though it consumes space, Eclipse is never slow. Download Eclipse here. You can also debug the code, write Junit tests, generate stubs and WSDLs, and easily add log statements. Eclipse is intuitive, and you can customize its features to suit your project. Apart from Java, you can use Eclipse as Python IDE, C/C++ IDE, and Scala using simple plug-ins. You can also download a lighter version of Eclipse, known as Easy Eclipseif you don’t want full features.
- NetBeans: NetBeans provides rapid UI development, cross-platform support, and the best support for Java technologies. It has powerful tools for HTML, JS, and CSS as well. NetBeans is fast, and you can even do project versioning and basic project management. NetBeans also supports C/C++, PHP, and JSP. You can refactor your code, check the correctness, and validate best practices—download Apache NetBeans.
For your own reasons, if you do not want to install an IDE on your system, you can also use an online compiler. Tutorialspoint provides a relatively faster online Java compiler compared to other online compilers.
How to Learn Java
Java is easy to learn, and you don’t have to spend too much time learning the concepts. Once you get the foundations right, you can start practicing.
If you already have the IDE set up on your system, try this simple program:
- Create a new project, let’s say, MyFirstJavaProj.
- Create a package named practice.
- Inside this package, create a class called MyFirstProgram.java, and check on the checkbox to add the main method: public static void main(String args)
- Just add the following code in the main method:
System.out.println("Welcome to the Java World!");
Run this program as a Java application, and the message will be displayed on the console.
Don’t worry about all the keywords used in the program. The point is that it takes just these many steps to make a Java project run! To understand these keywords and modifiers, read this short introduction to Java, and get started. You can take up the following excellent courses to further your practical learning experience:
Java Courses and Tutorials (Free and Paid)
This paid bestseller course from Udemy teaches core java skills, JavaEE, Spring framework, Android development, etc. The course focuses on Java 8 and 11 and also prepares you for the Oracle Java certification exam. It covers OOP concepts, collection, control flow statements, Generics, concurrency, network programming, and many more introductory and intermediate Java topics. It is reasonably priced, and you get discounts from time to time.
This is a specialization of about 4-6 months’ worth of content covering Java OOP, data structures and advanced data structures (like graphs), performance tuning, and tips and opportunities for clearing Java interviews. This is an intermediate course and has real-world projects and lectures from Google. You can take up all or individual courses of the specialization. Coursera works on a monthly subscription basis, so one can take up any number of courses.
This course covers the fundamental OOP concepts and how they are used in Java to develop web applications. You will be doing a lot of practical projects on different levels. It is an introductory course which doesn’t require any prerequisites. You will learn about conditionals, control flow, Arrays, ArrayList, Strings, inheritance, etc. The code also covers debugging exceptions, compile-time, and run-time errors. Codecademy has both free and paid courses, this is a free one.
4. Pluralsight Java courses
Pluralsight offers a range of Java courses for different levels. Each course is about 3 hours. You can start with the basic course, i.e., working with classes and interfaces, then take up the intermediate courses, like Java design patterns, web fundamentals, persistence API, etc. Take up the Pluralsight subscription, or if this is your first course, you can try it for free.
LinkedIn provides many short courses for learning Java. Few popular courses like Learning Java, Advanced Java Programming, and Introduction to Data Structures & Algorithms in Java are some good courses to start with. These three courses together cover the basic and advanced concepts of Java. LinkedIn provides a monthly subscription option, and the first month is free for learners.
For a detailed description and information of the best Java courses visit here.
Java Official Documentation
To learn more about Java's API and various utility methods, you should always look up the official API documentation page. You will also get to know the inheritance structure, interfaces, abstract classes, utility classes, and other OOP flavors through the API.
Most tutorials also give hands-on towards the end through projects. However, doing more projects without any external help will boost your confidence and increase your expertise level. Projects will help you master Java as quickly as possible.
Try out these 10 free Java projects for beginners from Hackr.io.
Other than these projects, you can also try simple projects on your own, like,
- building a house rental system or car rental system,
- Hangman game,
- online product purchase (adding products to cart and checkout),
- student information system,
- defect tracking system,
- e-mail spam filtering,
- railway ticket reservation system, and so on.
So, now you are done with learning Java through tutorials and have done some projects. You must be confident enough to take up certifications and add them to your resume. Certifications add a boost to your resume and give you an edge over other candidates with similar experience. Check out the Top Java certifications recommended by Java Developers.
Java Interview Questions
Now, it's time to put all your knowledge together and prepare for the big day. It would be best if you were thorough with the practical and concept-based questions of Java. For example, the evaluator may ask you to write code for the Fibonacci series or ask you about the implementation for Hashmap! Learn about Garbage collection, collection (LinkedList, Map, Tree, etc.), exception handling, and threads, amongst other topics! These are important questions that are asked in every Java interview. Some crucial questions are:
- Question: Differentiate between JVM, JRE, and JDK.
- Question: Explain access modifiers in Java.
- Question: What do you mean by Constructor?
- Question: Please explain the difference between String, String Builder, and String Buffer.
- Question: How do you make a thread in Java? Give examples.
- Question: How will you distinguish processes from threads?
- Question: Could you draw the Java Exception Hierarchy?
- Question: Explain exception propagation.
- Question: What is ordered and sorted concerning collections?
- Question: Please compare Serialization with Deserialization in Java.
Check out the complete list of 100+ top Java interview questions that will help you crack even that tough one!
- To sum up, we have covered the following: To learn Java, you must be familiar with a few programming concepts, like data structures like Array, LinkedList, Stack, Queue, Tree, Graph, etc., basic algorithms like binary search, linear search, bucket sort, quick sort, etc.
- Further, you should understand the foundational OOP concepts like Polymorphism, encapsulation, inheritance, abstraction, which form the basis of Java.
- For Java, it is always preferable to practice using an IDE, offline or online. You shouldn’t spend too much reading theory; instead, get yourself on coding simple programs as soon as possible.
- Start with basic programming concepts like variables, data types, operations, conditions, collection, loops, getting user inputs. Then go a bit deeper into concepts of file handling, connecting to the database, handling exceptions, threads, generics, garbage collection, design patterns, and then slowly move on to creating projects and web services.
- There is no task difficult or impossible. Even if you have no prior programming experience, you can become as good as a professional developer in no time with a little extra effort.
- Take up the courses and certifications to consistently improve your skills and keep yourself updated with the latest versions and methods.
We hope you enjoyed reading this guide to learning Java and it urges you to begin coding as soon as you read it. Try it out and let us know your feedback.
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