Hello World! Who's there?

Python2:

print "Hello World!"

Python3:

print ( "Hello World!" )

C:

#include <stdio.h>

int main (void)
{
    printf ("Hello World!\n");
    return 0;
}

C++:

#include <iostream>
using namespace std;

int main (void)
{
    cout << "Hello World!\n");
    return 0;
}

Java:

public class HelloWorld {
    public static void main (String[] args) {
        System.out.println ("Hello, World!");
    }
}