Are you new to programming and wondering which language to learn first? Java is a great choice.
Whether you're hoping to build web apps, mobile apps, or even large-scale business software systems, learning Java can open countless doors in the software development world.
In this guide, we'll walk you through basic Java fundamentals – and then you'll get a chance to write your own program!
We'll cover:
What Java is
Why devs should learn it
Java's unique features
How to create your first Java code
Ways to expand your learning and gain experience
Let's go!
Java is a popular programming language known for being easy to use and very versatile. It works for many types of devices, like computers and smartphones, thanks to something called the Java Virtual Machine (JVM), which allows Java programs to run anywhere without needing changes.
We call this feature "write once, run everywhere," and it's contributed to Java's widespread adoption across industries.
Java is also free and open-source, meaning anyone can use it or contribute to it. It has a large set of helpful tools and libraries, making it great for building all kinds of software, from simple mobile apps to huge business systems.
Here's where Java is used:
Web development: Java powers the back-end of many websites, using tools like Spring and Hibernate.
Mobile development: It’s the main language used for building Android apps.
Enterprise systems: Many big companies use Java to run their business software because it’s secure and reliable.
Big data: Java is key in technologies like Apache Hadoop and Apache Kafka, which handle large amounts of data.
Game development: Java works well for creating Android games, thanks to its ability to run on different devices.
Whether you’re working on a personal project or a large business system, Java provides a solid platform for building all kinds of software.
Java is a versatile, powerful language that many fields use, which makes learning it a smart choice for any dev – especially a new one who may not yet know what kind of coding career interests them.
Here's why learning Java can help shape your career:
Widely used: Java is used in web development, Android apps, desktop software, and large business systems. Its "write once, run anywhere" capability allows you to develop for multiple platforms.
High demand: Java developers are always in demand, providing strong career prospects in a variety of industries.
Huge community: Millions of developers use Java, offering extensive resources, tutorials, and community support for solving problems and learning new skills.
Trusted by big companies: Major players like Amazon, Google, and Netflix rely on Java for their critical applications, thanks to its reliability and security.
Let’s dive into what makes this language tick. Here’s a breakdown of key concepts that will help you understand how Java works.
See how the following slide takes apart almost the same code we just saw above and then snaps the pieces together, kind of like Lego blocks.
Class name: In Java, code is organized into "classes," which act like blueprints for your program. For example, the line public class MyJavaApp creates a class named MyJavaApp.
The name of the file must match the class name. If your class is called MyJavaApp, the file should be named MyJavaApp.java. If the names don’t match, Java will give you an error when you try to run the program.
Main method: Every Java program starts executing from the main method. It is declared with public static void main(String[] args).
Here’s what each part means:
public: The method can be accessed from anywhere.
static: It belongs to the class itself, not an instance of the class.
void: The method doesn’t return any value.
String[] args: This is an array of strings that holds any arguments passed to the program from the command line.
To build a strong foundation in Java, you'll want to focus first on its building blocks. Let's explore those now.
In Java, you must specify the type of data a variable will hold. This is called being statically typed. There are two main types of data:
Primitive Data Types: Basic types like numbers and characters (e.g., int, double, char).
Non-Primitive Data Types: More complex types like objects or arrays, which you define.
Some common data types include:
int: For integers
double: For floating-point numbers
char: For single characters
String: For strings of characters (objects)
Control structures allow you to dictate the flow of your program:
If-else statements: For decision-making
Loops: Such as for loops, while loops, and do-while loops for repetition of a block of code
Switch statements: For choosing one out of multiple code block to be executed
Java is an "object-oriented programming language (OOP)," which refers to a type of language that organizes code by grouping related tasks and data into "objects." This makes programs easier to manage, use, and expand as they grow.
Classes and objects: The most building blocks of Java codes
Inheritance: Makes it possible for one class to inherit class another by borrowing its field and methods
Polymorphism: Enables one interface to be used for a general class of actions
Encapsulation: The process of grouping the data (attributes) and the operations performed on the data and the data group (functions) under one unit or class
Abstraction: Hiding the implementation details and showing only the functionality
In Java, exception handling helps prevent your program from crashing when errors occur. You use try, catch, and finally blocks to handle exceptions:
try: The code that might cause an error goes here.
catch: This block handles the error if one occurs.
finally: This block runs after try and catch, whether there’s an error or not.
In Java, exceptions are errors that happen while the program is running. Here are a few common ones:
NullPointerException: This happens when you try to use an object that hasn’t been properly set up (initialized).
ArrayIndexOutOfBoundsException: This occurs when you try to access an item from an array using an index that doesn’t exist (for example, asking for the 5th item in an array that only has 4 items).
ArithmeticException: This error comes up when you try to do an illegal math operation, like dividing a number by zero.
Now that you’ve learned the basics about what Java is and where it’s used, it’s time to start writing some actual code!
But before we dive in, we need to set up your computer so you can run Java programs. This involves installing a couple of tools that will help you write and test your Java code.
To start coding in Java, you need to set up something called a development environment. Don’t worry—it’s easier than it sounds! You’ll need to install two things:
Java Development Kit (JDK): This gives you all the tools you need to write and run Java code.
Integrated Development Environment (IDE): This is a program where you’ll write your Java code and test it.
The JDK is like a toolbox for Java programming. It includes the Java compiler (which turns your code into something the computer can understand) and the Java Virtual Machine (JVM), which runs your programs.
Here’s how to install it:
Go to Oracle’s website and download the latest version of the JDK for your computer.
Follow the installation instructions based on whether you’re using Windows, macOS, or Linux.
After installing, you’ll need to set something called the JAVA_HOME environment variable, which helps your computer find the JDK. Follow the instructions provided during installation for your operating system.
An IDE (Integrated Development Environment) is a special program where you write, test, and debug your code. Think of it as your workspace for coding — like a word processor, but for programming! Here are some popular Java IDEs you can choose from:
IntelliJ IDEA
Why it's great: IntelliJ IDEA helps you write code faster with its smart features like auto-completing your code and suggesting improvements. It’s perfect if you’re working on bigger projects, especially since it works really well with tools like Git (for version control) and databases.
Best for: Developers working on more complex projects or who want extra help writing cleaner code.
Eclipse:
Why it's great: Eclipse is an open-source IDE that you can customize with plugins to fit your needs. It’s powerful and works with lots of programming languages, not just Java. However, it might feel a bit heavy for small projects.
Best for: Developers who want flexibility and are working on larger, enterprise-level projects.
Apache NetBeans:
Why it's great: NetBeans is free and easy to use, making it a great choice for beginners. It has a simple, no-frills interface that lets you focus on learning Java without getting overwhelmed by extra features.
Best for: Beginners who want something straightforward and easy to get started with.
Okay, once you've installed an IDE of your preference, you're all set to begin writing actual Java code!
Let's give it a try.
Once your environment is set up, it’s time to write your first Java code snippet! A classic way to start is by creating a simple “Hello, World!” program:
Open your IDE and create a new project.
Create a new Java class and name it HelloWorld.
Write the following code:
public class HelloWorld {public static void main(String[] args) {System.out.println("Hello, World!");}}
Click the “Run” button. You should see “Hello, World!” printed on the console.
Now, it’s time for a challenge. Write a Java program that prints your name in the code widget below.
Do not change the class name YourNameApp.
class YourNameApp {// Write code here!}
Now, let’s take a look at a few more examples before diving deep into its components:
public class MyJavaApp {// Main method - entry point of the programpublic static void main(String[] args) {// Use the Math.round() function to round the number to the nearest integer// Store the rounded value in a long variable named 'roundedNumber'double roundedNumber = Math.round(3.14159);// Print the rounded numberSystem.out.println("Rounded number: " + roundedNumber);}}
Now that you've got some hands-on experience working with Java, we can explore ways to expand your knowledge.
Java offers a variety of libraries and APIs that can streamline your development process. They contain pre-written code that you can use to save time and avoid reinventing the wheel.
The Java Standard Library provides many useful functions that handle everyday tasks, such as:
Working with text (like changing or formatting strings of words)
Reading from or writing to files (input/output operations)
Storing and organizing data (using tools like lists or maps)
Java collections framework: Understand how to work with collections like ArrayList, HashMap, and HashSet.
Java IO and NIO: Learn how to handle input and output, including file reading and writing.
Java concurrency: Explore how to write multi-threaded programs using Java’s concurrency utilities.
Familiarity with these libraries will make your code more efficient and reduce the amount of code you need to write.
After mastering the basics, you can check out more advanced Java topics. These might include:
Java networking: Learn how to create networked applications using sockets.
Java Database Connectivity (JDBC): Understand how to connect your Java applications to a database.
Java frameworks: Explore popular Java frameworks like Spring and Hibernate, which are widely used in enterprise-level applications.
Advanced topics will prepare you for more complex projects and give you the skills needed for professional development.
The most effective method for learning Java is through hands-on practice. Begin with easy tasks and progressively transition to harder challenges.
Here are a few suggestions for practicing:
Basic calculator: Develop a software which can conduct fundamental mathematical functions such as adding, subtracting, multiplying, and dividing.
Bank account management: Create a basic bank account system that allows for depositing, withdrawing, and checking balance.
Student grade system: Develop a system that computes and saves students' grades.
These activities will strengthen your grasp of Java syntax, OOP principles, and control structures.
Start Your Java Journey Now
This course focuses exclusively on teaching Java to beginners and demystifies procedural programming by grounding each concept in a hands-on project. You’ll start by learning built-in input and output methods, followed by user-defined methods. As you progress, you'll explore basic data types and apply them in sequential, selective, and iterative program structures. Finally, you'll use these concepts to complete an engaging project. By the end, you'll develop a fascination with Java programming, making it an excellent start to a career in computing for anyone looking to learn Java.
Once you grasp the basics well, start building small projects to apply your knowledge. This could be a simple command-line application, a basic calculator, or even a simple game. The key is to practice and build something tangible.
Here are some tips to guide you in your project-building journey.
To-do list application: Create an app that allows users to add, remove, and mark tasks as completed.
Simple inventory system: Build a program that tracks items in a store, including stock levels and prices.
Basic chat application: Write a simple text-based chat program that allows two users to send messages back and forth.
Working on projects will give you a deeper understanding of Java and help you learn how to structure and manage larger codebases.
Learning Java doesn’t have to be a solitary journey. Join online communities, participate in forums, and attend local meetups.
The Java community is vast and welcoming, and engaging with other learners and developers can provide you with support, resources, and motivation.
Stack Overflow: Ask questions and learn from experienced developers.
GitHub: Contribute to open-source Java projects and build your portfolio.
Reddit’s/Java: Discuss, share resources, and stay updated with the latest Java news.
Being part of a community can accelerate your learning and keep you motivated.
Learning Java might feel overwhelming at first, but by taking it step by step, you’ll gradually build your skills and confidence. You've already built your first program!
Start with the basics, practice regularly, and don’t be afraid to seek help from the vast Java community. With dedication, you’ll soon be well on your way to mastering Java and unlocking exciting opportunities in software development.
Java’s versatility makes it a great choice for both beginners and experienced developers. So, why wait? Dive in, start learning, and enjoy the process!
This Skill Path begins with Java basics and explores topics like object-oriented programming and data structures. Next, you’ll cover Java programming, including core concepts and object-oriented principles. Finally, you’ll learn about algorithms, databases, REST API automation, and software quality assurance. The Skill Path concludes with practical projects and coding challenges to prepare you for a programming career.
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