import java.util.ArrayList;
/**
 * 
 */
public class Purse
{
    public Purse()
    {
        coins = new ArrayList<String>();
    }
    
    void addCoin(String coinName)
    {
        coins.add(coinName);
    }
    
    public String toString()
    {
        if (coins.size() == 0)
            return "Purse[]";
        
        String coinsString = coins.get(0);
        
        for (int i = 0; i < coins.size(); i++)
        {
            coinsString = coinsString + "," + coins.get(i);
        }
        return "Purse[" + coinsString + "]";
    }
    
    public String firstCoin()
    {
        String firstCoin = coins.get(0);
        return firstCoin;
    }
    
    private ArrayList<String> coins;
}

-------------------- another class -----------------------

public class PurseTester
{
    public static void main(String[] args)
    {
        Purse testPurse = new Purse();
        
        testPurse.addCoin("Quarter");
        testPurse.addCoin("Dime");
        testPurse.addCoin("Nickel");
        testPurse.addCoin("Dime");
        
        System.out.println(testPurse.toString());
    }
}