What happens if there are multiple main methods inside one class in Java?

 It is not allowed to have multiple main methods within a single class in Java. The main method is the entry point for a Java program, and there can be only one entry point for a program.

If you try to define multiple main methods within a single class, you will get a compile-time error. For example:

public class Main { public static void main(String[] args) { // code for main method 1 } public static void main(String[] args) { // code for main method 2 } }

This code will not compile because there are two main methods with the same signature defined in the Main class. The compiler will give an error message similar to:

error: main method is already defined in class Main

It is allowed to have multiple classes in a Java program, and each of these classes can have a main method. However, only one of the main methods will be the entry point for the program, and the others will be ignored.