Please help this dummy...How this program works??

Question

Hi, I am new in Java...I just bought a book and start to learn the java from that book. Here is one of the project exercise and seems that it is difficult for me to understand the flow of the program.
class HelpClassDemo {
public static void main(String args [])
throws java.io.IOException () {
char choice;
Help hlpobj = new Help;
for(;;) {
do {
hlpobj.showmenu();
do {
choice = (char) System.in.read () ;
} while (choice == '\n' | choice == '\r');
} while ( !hlpobj.isvalid (choice) );
if(choice == 'q' ) break;
System.out.println("\n");
hlpobj.helpon(choice);
Thats what the program code. I don't understand especially after the " } while( !hlpobj.isvalid(choice)); " part. And i don't know what is !hlpobj means....
Please help.....

Answer 1

is it indicated the opposite of hlpobj object or the
opposite of isvalid method?the opposite of the result of isvalid method.
if isvalid method returns true then the opposite of true which false because of the not sign(!)
*/