Learn Java Programming

Master Java from basics to advanced topics with concise lessons and practical examples. Follow a structured path inspired by reputable learning resources.

Start Learning Try Java Online

Reference guide: Programiz — Getting Started with Java [0]

Tutorial Contents
Getting Started
Basics
Control Flow
Methods & Arrays
Object-Oriented Programming
Exceptions

Java Variables

Variables store values. Declare with a type followed by a name.

int age = 25;
double price = 19.99;
boolean isActive = true;
String name = "Alice";
final double PI = 3.14159; // constant
  • final makes a variable constant; it must be assigned once.
  • Locals have no default values—initialize before use. Fields do have defaults.
  • Prefer descriptive names; avoid single letters except for short-lived loop counters.
  • Use BigDecimal for precise financial calculations instead of double.

Java Tutorial FAQs

How do I run Java online?
Use the Java Online Compiler to write and execute Java directly in your browser—no setup needed. Click "Try Java Online" above to get started.
How do I install Java on Windows?
Download the JDK installer, run it, then set JAVA_HOME and update the Path variable to include the JDK bin directory. Verify with java --version. [0]
How do I install Java on macOS?
Install the appropriate JDK DMG (x64 or ARM64). In your shell profile, set export JAVA_HOME=$(/usr/libexec/java_home) and update PATH to include $JAVA_HOME/bin. Verify with java --version. [0]
Do I need the JDK to compile Java?
Yes. The JDK provides the compiler (javac) and tools needed to build Java applications. For quick tests, the online compiler is a convenient alternative.
What is Java used for?
Java powers cross-platform applications including web services, Android apps, enterprise systems, and tooling built on the JVM. Its strong OOP model and rich libraries make it versatile.

Learn Java the Practical Way

Whether you’re new to programming or expanding your skills, this Java tutorial focuses on hands-on learning. Each topic pairs clear explanations with short, working examples that you can run online. Move from fundamentals—variables, data types, and control flow—to core OOP concepts like classes, inheritance, and interfaces. Along the way, you’ll see idiomatic Java patterns and simple best practices that build confidence.

Why this guide? It’s designed for real-world use: fast to read, easy to try, and friendly on mobile. Bookmark it and return whenever you need a refresher or a quick example.