First Java Program
Writing Your First Java Program
Let’s write a simple Java program:
google.com, pub-8434817042454839, DIRECT, f08c47fec0942fa0
public class HelloWorld {
public static void main(String[] args) {
System.out.println(“Hello, World!”);
}
}
public static void main(String[] args) {
System.out.println(“Hello, World!”);
}
}
Understanding the Code
Class Declaration
public class HelloWorld
Defines a class named HelloWorld.
Main Method
public static void main(String[] args)
Entry point of the program.
Print Statement
System.out.println(“Hello, World!”);
Displays output on the screen.
Compilation and Execution
Step 1: Compile
javac HelloWorld.java
Step 2: Run
java HelloWorld
Java Program Structure
A basic Java program includes:
- Class definition
- Main method
- Statements
- Output functions
Java Syntax Rules
- Java is case-sensitive
- Every statement ends with
; - Class name must match file name
- Code runs inside methods
Common Beginner Mistakes
- Missing semicolons
- Incorrect class name
- Wrong file name
- Case mismatch
