For what it's worth, Wikipedia calls it the "Hello world" program, but indicates there should be a comma in the output:

A "Hello world" program is a computer program that outputs "Hello, world" on a display device.

Other sources make this two-word phrase an exclamation:

Lesson: A Closer Look at the "Hello World!" Application

Now that you've seen the "Hello World!" application (and perhaps even compiled and run it), you might be wondering how it works. Here again is its code:

class HelloWorldApp {
public static void main(String[] args) {
System.out.println("Hello World!"); // Display the string.
}
}

Other times, both the comma and the exclamation point are used:

Hello, world! programs make the text "Hello, world!" appear on a computer screen.

Incidentally, this website lists several Hello world programs, most of which use both the comma and the exclamation point, although there are a few exceptions, like this one:

xhello db 'Hello world !!!$'

Ultimately, though, in this context, it matters very little what's between the quotation marks, so long as the program runs.

For what it's worth, Wikipedia calls it the "Hello world" program, but indicates there should be a comma in the output:

A "Hello world" program is a computer program that outputs "Hello, world" on a display device.

Other sources make this two-word phrase an exclamation:

Lesson: A Closer Look at the "Hello World!" Application

Now that you've seen the "Hello World!" application (and perhaps even compiled and run it), you might be wondering how it works. Here again is its code:

class HelloWorldApp {

    public static void main(String[] args) {
        System.out.println("Hello World!"); // Display the string.
    }
}

Other times, both the comma and the exclamation point are used:

Hello, world! programs make the text "Hello, world!" appear on a computer screen.

Incidentally, this website lists several Hello world programs, most of which use both the comma and the exclamation point, although there are a few exceptions, like this one:

xhello db 'Hello world !!!$'

Ultimately, though, in this context, it matters very little what's between the quotation marks, so long as the program runs.

For what it's worth, Wikipedia calls it the "Hello world" program, but indicates there should be a comma in the output:

A "Hello world" program is a computer program that outputs "Hello, world" on a display device.

Other sources make this two-word phrase an exclamation:

Lesson: A Closer Look at the "Hello World!" Application

Now that you've seen the "Hello World!" application (and perhaps even compiled and run it), you might be wondering how it works. Here again is its code:

class HelloWorldApp {
public static void main(String[] args) {
System.out.println("Hello World!"); // Display the string.
}
}

Other times, both the comma and the exclamation point are used:

Hello, world! programs make the text "Hello, world!" appear on a computer screen.

Incidentally, this website lists several Hello world programs, most of which use both the comma and the exclamation point, although there are a few exceptions, like this one:

xhello db 'Hello world !!!$'

Ultimately, though, I agree with BillyNair above. In this context, it matters very little what's between the quotation marks, so long as the program runs.

For what it's worth, Wikipedia calls it the "Hello world" program, but indicates there should be a comma in the output:

A "Hello world" program is a computer program that outputs "Hello, world" on a display device.

Other sources make this two-word phrase an exclamation:

Lesson: A Closer Look at the "Hello World!" Application

Now that you've seen the "Hello World!" application (and perhaps even compiled and run it), you might be wondering how it works. Here again is its code:

class HelloWorldApp {
public static void main(String[] args) {
System.out.println("Hello World!"); // Display the string.
}
}

Other times, both the comma and the exclamation point are used:

Hello, world! programs make the text "Hello, world!" appear on a computer screen.

Incidentally, this website lists several Hello world programs, most of which use both the comma and the exclamation point, although there are a few exceptions, like this one:

xhello db 'Hello world !!!$'

Ultimately, though, in this context, it matters very little what's between the quotation marks, so long as the program runs.