Loading
Java Introduction
What is Java?

Java is a high-level, object-oriented programming language used to build everything from desktop applications to mobile apps, enterprise systems, and cloud-based services.

Originally developed by James Gosling in 1995 at Sun Microsystems (now owned by Oracle), Java is known for its philosophy:


Write Once, Run Anywhere 

This means code written in Java can run on any system that has a Java Virtual Machine (JVM), without modification.



Key Features of Java

  • Platform Independent – Runs on Windows, Mac, Linux, etc. No need to change code for different systems.
  • Object-Oriented – Everything is based on classes and objects, making code reusable and easy to manage.
  • Secure & Robust – Offers strong memory management, built-in security, and exception handling.
  • Multithreaded – Supports running multiple tasks simultaneously for better performance.
  • Massive Community Support – Backed by millions of developers, a rich ecosystem of tools, and countless libraries/frameworks.


How Java Works

  • Write Code You write your code in a .java file.
  • Compile The javac compiler converts your code into bytecode (.class file).
  • Execute The JVM (Java Virtual Machine) runs the bytecode on any platform.

Tip: You do not need to memorize the code execution process. The Java compiler and JVM handle it for you!


Your First Java Program

Here is a simple Java program that prints "Hello, Java!" to the screen:

// First Java Program
public class HelloJava {
    public static void main(String[] args) {
        System.out.println("Hello, Java!");
    }
}


Output:

Hello, Java!


Where is Java Used?

Java powers many real world applications, including:

  • Web Development:  Frameworks like Spring Boot and Hibernate
  • Android Development:  Apps built with Java and Kotlin
  • Enterprise Software:  Banking systems, CRM, ERP solutions
  • Game Development:  Popular games like Minecraft and Runescape
  • Cloud & Big Data:  Technologies like Hadoop and Apache Spark


Two Minute Drill

  • Java is powerful and object oriented.
  • Write once, run anywhere with the help of JVM.
  • Secure and reliable with automatic memory management.