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Introduction

4 min read ·

Java is one of the most popular programming languages in the world. It is widely used for building desktop applications, web applications, mobile apps, enterprise software, and backend systems.
This Java tutorial is designed for beginners who want to learn Java from scratch step by step.
Java is simple, secure, platform independent, and object oriented. Because of these features, Java is used by millions of developers and companies worldwide.

What is Java?

Java is a high level programming language developed by Sun Microsystems in 1995.
Later, Java became part of Oracle.
Java allows developers to write code once and run it on different operating systems.
This concept is known as:
Write Once, Run Anywhere
Note

Java code runs on the Java Virtual Machine called JVM, which makes Java platform independent.

Why Learn Java?

Java is one of the most trusted programming languages in the software industry.
Java is used in:
  • Android applications
  • Banking systems
  • Enterprise software
  • Cloud applications
  • Web development
  • Big data technologies
Learning Java helps beginners build strong programming fundamentals.

Features of Java

Java provides many powerful features.

Simple

Java syntax is easy to learn and understand.

Object Oriented

Java follows object oriented programming concepts like:
  • Class
  • Object
  • Inheritance
  • Polymorphism

Platform Independent

Java programs can run on multiple operating systems.

Secure

Java provides strong security features for applications.

Robust

Java has strong memory management and error handling.

Multithreading

Java supports running multiple tasks simultaneously.
Pro Tip

Java is one of the best programming languages for beginners who want to learn object oriented programming properly.

History of Java

Java was created by James Gosling and his team.
Initially, the language was called Oak.
Later, it was renamed Java.
The main goal behind Java was to create portable and secure software for different devices.
Today Java powers millions of applications worldwide.

How Java Works?

Java programs follow a special execution process.

Step 1

Write Java code inside a .java file.

Step 2

The Java compiler converts code into bytecode.

Step 3

The Java Virtual Machine executes the bytecode.
Because of JVM, Java programs can run on different operating systems without modification.

Java Program Example

Example

Output

Understanding the Program

class Main

Defines a class named Main.

main()

Execution of Java program starts from the main() method.

System.out.println()

Used to print output on the screen.
Goal Achieved

You have written your first Java program successfully.

Java File Extension

Java source files are saved using the .java extension.

Example

Where Java is Used?

Java is used in multiple technologies and industries.

Android Development

Many Android applications are built using Java.

Banking Systems

Banks use Java for secure transactions and backend systems.

Web Applications

Java is used for enterprise level web applications.

Cloud Applications

Java is widely used in cloud based systems.

Big Data

Technologies like Hadoop use Java internally.
Real World Scenario

Large banking applications use Java because it provides high security, scalability, and reliability.

Advantages of Java

  • Easy to learn
  • Secure programming language
  • Large community support
  • Platform independent
  • Strong performance
  • Huge number of libraries and frameworks

Java Development Kit

To run Java programs, developers need Java Development Kit called JDK.
JDK contains:
  • Java compiler
  • JVM
  • Development tools
Without JDK, Java programs cannot be compiled and executed.

Common Beginner Mistakes

Missing Semicolon

Incorrect:
Correct:

Incorrect File Name

If class name is Main, filename should also be:

Incorrect Uppercase and Lowercase

Java is case sensitive.
and
are different.
Caution

Small syntax mistakes in Java can generate compilation errors.

Why Beginners Should Learn Java?

Java helps beginners understand:
  • Programming logic
  • Object oriented programming
  • Software development concepts
  • Backend development
Java is also highly important for coding interviews and software engineering jobs.
After Java, developers usually learn:
  • JDBC
  • Spring Boot
  • Hibernate
  • Android Development

Exercise

Create a Java program that prints your name and city.

Example