need help in a easy java game

[m00se]

need help in a battleship kinda game

If i get a hit i can choose the same number to win the game .. how can i make it so that i can only pick 1 number once?

public class simpleDotComDrive {
	public static void main (String[] args){
		int numOfGuesses = 0;
		GameHelper helper = new GameHelper();
		simpleDotCom dot = new simpleDotCom();
		int randomNum = (int) (Math.random() * 5);
		int[] locations = {randomNum,randomNum+1,randomNum+2**;
		dot.setLocationCells(locations);
		boolean isAlive = true;
		
		while (isAlive == true){
		
		String userGuess = helper.getUserInput("enter a number");
		String result = dot.checkYourSelf(userGuess);
		numOfGuesses++;
		if (result.equals("kill")){
			isAlive = false;
				System.out.println(numOfGuesses + " guesses");
			**
		**
**
**

public class simpleDotCom {
	int [] locationCells;
	int numOfHits = 0;
	
	public void setLocationCells(int[] locs){
		locationCells = locs;
	**
	
	public String checkYourSelf(String stringGuess){
		
		int guess = Integer.parseInt (stringGuess);
		String result = "miss";
		for (int i = 0;i < locationCells.length; i++)
			{
			if (guess == locationCells[i]){
			
			result = "hit";
			numOfHits++;
			break;
			**
		**
		if (numOfHits == locationCells.length)
		{
			result = "kill";
		**
		System.out.println(result);
			return result;
	**

**

import java.io.*;
public class GameHelper {
		public String getUserInput(String prompt){
		String inputLine = null;
		System.out.print(prompt + " ");
		try{
		BufferedReader is = new BufferedReader(new InputStreamReader(System.in)
		);
		inputLine = is.readLine();
		if (inputLine.length() == 0) return null;
		
		** catch (IOException e) {
		System.out.println("IOException: " + e);
		** return inputLine;
		**
	
	

**