Displaying a string with hidden characters

I have a test for a class that displays a word randomly chosen from an array.

I'm trying to display the word with several chars hidden

I have taken the string, then converted it to an array of chars, but I'm confused as to where to go from here.

import java.util.Scanner;
public class wordTest {
    public static void main (String args[])
    {
        Scanner scanner = new Scanner(System.in);
        String readString = scanner.nextLine();
         char[] stringArray;


         String [] gamewords = { "dog", "cat", "coffee", "tag", "godzilla", "gamera", "lightning", "flash", "spoon", "steak", "moonshine", "whiskey", "tango", "foxtrot", "ganymede" 
                 , "saturn", "enterprise", "reliant", "defiant", "doom", "galapagos", "jidai", "sengoku"};

        arrayWords wl = new arrayWords();
     // Words w = new Words();
        Word n = new Word();


    int a = 0;
        int b = gamewords.length;


        RandNum rand = new RandNum(a,b);
        n.setWord(gamewords[rand.nextRandomIntegerInRange()]);

        stringArray = n.getWord().toCharArray();
        int blank1 = 1;
        int blank2 = 4; 

        RandNum blanks = new RandNum(blank1,blank2);



        n.setWord(gamewords[rand.nextRandomIntegerInRange()]);


            do{

                int i = 0;
                //scanner.nextLine();
                  for( i = 0; i < stringArray.length; i++){
                      for( i = 0 ; i < blanks.nextRandomIntegerInRange() ; i++ ){

                          stringArray[i] = '*';
                      }
                          System.out.println(stringArray[i]);

                      }


             }while(scanner.nextLine().equals(""));


    }


    }