What is Java?
Java is a popular, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is used for building cross-platform applications — from desktop to web, mobile, and server-side apps.
- Platform-independent via the Java Virtual Machine (JVM).
- Strongly typed and memory-managed (automatic garbage collection).
- Large ecosystem: libraries, frameworks and tooling.
History of Java
Here are the key milestones in Java's history (short and simple):
- 1991: Java started as the Green Project at Sun Microsystems.
- 1995: Officially released as Java 1.0.
- 2006: Sun released core Java under the GPL license.
- 2010+: Oracle continued Java development; Java has regular feature releases (e.g., Java 8, 11, 17 LTS versions).
Tools You Will Need
To write, compile and run Java programs you commonly need:
- JDK — Java Development Kit (e.g., OpenJDK 17 or 21). Install from Adoptium/Oracle.
- IDE — IntelliJ IDEA, Eclipse or Visual Studio Code with Java extension.
- Terminal — Command prompt or PowerShell to run
javacandjava. - Optional — Build tools: Maven or Gradle for larger projects.
Quick Try — Hello World
Copy and paste the following into a file called HelloWorld.java, then compile and run it:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, Java!");
}
}
Local commands (PowerShell):
Copy the Hello World snippet into a file named HelloWorld.java and run:
javac HelloWorld.java — compile
java HelloWorld — run
Or try it online with:
What's Next (Suggested Learning Path)
After this overview, continue with the following topics for a smooth learning journey:
- Basic syntax: variables, data types and operators.
- Control flow: if/else, loops (for, while), switch-case.
- Methods and modular programming.
- Classes & objects, constructors and access modifiers.
- Collections and arrays — start with the Arrays Chapter.