do while loop

/*  So the age old knock knock joke goes like this:
        Person A:  Knock Knock.
        Person B:  Who's there?
        Person A:  Banana
        Person B:  Banana who?
        ...This repeats until Person A answers Orange
        Person A:  Orange
        Person B:  Orange who?
        Person A:  Orange you glad I didn't say Banana again?
*/

//Here is the prompting code
console.printf("Knock Knock.\n");
Sting who;
boolean isInvalidWord;
do {
    who = console.readLine("Who's there?  ");
    isInvalidWord = (noun.equalsIgnoreCase("banana");
    if (inInvalidWord) {
      console.printf("%s who?\n" , who);
    }
   } while((who.equalsIgnoreCase("banana")
    console.printf("%s who?\n" , who);
  }
}