Hello World is a simple Java program. (This information came from the Oracle website Java tutorial.)

What information must be included in the comments at the top of a program? What is a test plan? I am looking for general answer not specific to this or any other program.

/**
* The HelloWorldApp class implements an application that
* simply prints "Hello World!" to standard output.
*/
class HelloWorldApp
{
public static void main(String[] args)
{
System.out.println("Hello World!"); // Display the string.
}
}