The main Method: Entry Point of Execution

What you'll learn: How the main method acts as the starting line for every Java program and why its signature must be exactly right.

Why Programs Need a Starting Point

Imagine you're reading a book. You need to know where to start reading—usually page 1, chapter 1. Similarly, when the JVM runs your program, it needs to know exactly where to begin executing your code. In Java, that starting point is always a method called main.

The Required Signature

Every runnable Java program must include this exact line:

public static void main(String[] args)

Let's break down why each word matters (you'll understand the details later, but here's the preview):

• public – The JVM needs to access this method from outside your code
• static – The JVM must call this method without creating an object first
• void – This method doesn't return any value back to the JVM
• main – The specific name the JVM looks for (must be lowercase "main")
• String[] args – Allows you to pass text information when starting your program

Think of this signature as a special contract between you and the JVM. If you spell something wrong (Main instead of main) or leave out a word (static), the JVM won't recognize it as the entry point and your program won't run.

What Happens When You Run Your Program

When you type java YourProgram in your terminal, the JVM searches your compiled file for this exact main method signature. Once found, it starts executing the code inside that method, line by line, from top to bottom.

Key Takeaway: The public static void main(String[] args) method is the required entry point for all Java programs—the JVM looks for this exact signature to know where to start execution.