Main Method

The main method is the entry point for every Java application - it’s where program execution begins.

Basic Structure

public class MyClass {
  public static void main(String[] args) {
    // Program execution starts here
    System.out.println("Hello, World!");
  }
}

Main Method Components

• public: Access modifier making the method accessible from anywhere
• static: Makes the method accessible without creating an instance of the class
• void: Return type indicating the method doesn’t return any value
• main: Method name (must be exactly “main”)
• String[] args: Command-line arguments passed to the program

Command-Line Arguments

The String[] args parameter allows passing information to your program when it starts:

public static void main(String[] args) {
  for (int i = 0; i < args.length; i++) {
    System.out.println("Argument " + i + ": " + args[i]);
  }
}

When executed with: java MyClass first second third Output:

Argument 0: first
Argument 1: second
Argument 2: third

Multiple Main Methods

• A Java project can have multiple classes with main methods
• The JVM executes the main method in the class specified at runtime
• This allows different entry points for different purposes

Best Practices

• Keep the main method simple and focused on program initialization
• Consider extracting logic to separate methods and classes
• Use command-line arguments for configuration when appropriate