//HelloWorld.java
// slash slash is start of "comment" to end of line. 
//comments are skipped/ignored by compiler.  they're for people, 
//help us understand the program.

//can have one "public" "class" in a file.
//filename must be same as the public class.
//you choose name of the class.  
//names can only have letters and digits and must start with letter.  
//public means it's accessible/usable by other classes.
//Java program's code is organized into classes
//(but in this course, all our programs will be one class only,
//  so the public class is the complete program.)
//public, class, static (the blue words in JCreator) are part of the 
//builtin vocabulary ("reserved words"/"keywords") of Java.

public class HelloWorld {
    //required braces are used to indicate beginning and end of container.    

    //application has a main "method".  it's where program begins.
    //method is a named bunch of code.
    //a class could have other methods 
    //  (but in this course, our applications will have main only).
    public static void main (String[] args)   //must be this incantation
    {
	//output to DOS box by System.out.println method
	System.out.println ("Hello World!");
	//double quoted is a "string" (sequence of characters/text).
	//here it's the "parameter"/"argument" given/passed to the method.
	//semicolon indicates end of a statement.
	//every statement must be terminated with a ;
    }
    //notice the indentation.  each level is 4 spaces.
    //try to keep each line less than 80 chars wide.
}