return type of main in java

Question

I like to know why only void return type for main method in java.

public static void main(String [] args)

Why there is no other return types other than void for main method.

Thanks

Answer 1

What were you expecting to return?

In C you typically return an int exit code. However, in a multithreaded system this doesn't make much sense. Typically a Java program will start a number of threads. The main thread will often return more or less immediately.

System.exit can be used to exit with a specific exit code.

Answer 2

The short answer is: Because that's what the language specification says.

In today's commonly used operating systems (Windows and Unix families), the only "return value" from a process is an exit status, which is a small number (usually 8-bit). This value can be returned from a Java program using the System.exit(int) method:

public static void exit(int status)

Terminates the currently running Java Virtual Machine. The argument serves as a status code; by convention, a nonzero status code indicates abnormal termination.