Java 2025: Complete Beginner's Guide from Scratch

Introduction to Java: Why This Language is Relevant in 2025

Java remains one of the most in-demand programming languages in the world. In 2025, it still holds leading positions in enterprise development, mobile application creation (Android), web services, and cloud solutions. If you have decided to start your journey in IT, Java is an excellent choice thanks to its strong typing, huge community, and rich ecosystem of tools.

In this article, we will break down where to start learning Java in 2025: from installing the necessary software to writing your first meaningful program. You will get a clear action plan and understand the core concepts of the language.

1. Setting Up the Development Environment: JDK, IDE, and First Program

Before writing code, you need to install the Java Development Kit (JDK) — a set of tools for developing, compiling, and running Java applications.

Step 1: Installing JDK 21 or 22

In 2025, it is recommended to use the latest LTS version (Long-Term Support) — Java 21 or the fresh Java 22. You can download the JDK from the official Oracle website or use OpenJDK (e.g., from Adoptium).

# Checking the installation after installing JDKjava --version# You should see something like:# openjdk 21.0.2 2024-01-16 LTS

Step 2: Choosing an IDE

For comfortable work, a beginner can use:

IntelliJ IDEA Community Edition — the best free IDE for Java.
VS Code with the Extension Pack for Java plugin — a lightweight alternative.
Eclipse — a classic, but the interface may seem outdated.

Step 3: First Program "Hello, World!"

Create a file Main.java and write the following code:

public class Main {    public static void main(String[] args) {        System.out.println("Hello, Java 2025 world!");    }}

Run the program via the IDE or command line:

javac Main.java   # compilationjava Main         # execution

If you saw the line "Hello, Java 2025 world!" — everything works!

2. Syntax Basics: Variables, Data Types, and Operators

Java is a strongly typed language. This means that every variable must have a declared type.

Primitive Data Types

int — integer number (32 bits)
double — floating-point number (64 bits)
boolean — logical value (true/false)
char — a single character in single quotes

Example of Working with Variables

public class VariablesDemo {    public static void main(String[] args) {        int age = 25;        double price = 199.99;        boolean isStudent = true;        char grade = 'A';

        System.out.println("Age: " + age);        System.out.println("Price: " + price);        System.out.println("Student: " + isStudent);        System.out.println("Grade: " + grade);    }}

Conditional Statements and Loops

The basic constructs of Java are similar to C/C++:

public class ControlFlow {    public static void main(String[] args) {        int number = 10;

        // if-else        if (number > 0) {            System.out.println("The number is positive");        } else {            System.out.println("The number is negative or zero");        }

        // for loop        for (int i = 0; i < 5; i++) {            System.out.println("Iteration: " + i);        }

        // while loop        int count = 0;        while (count < 3) {            System.out.println("Count: " + count);            count++;        }    }}