Code won't compile! (cannot resolve symbol)

Question

I'm having trouble compiling some code. Do any of you guys know why this won't work?
* Simulation of one die (now modified for multiple with inheritance)
* @author Kristian Hermansen
* @version 3/14/2004 (Section 2 honors)
public class Experiment1 extends DiceExperiment
// instance variables
int numSides = 6;
int numDice = 1;
int lowCombo = 1;
Object[] obj;
int[] array;
public Experiment1()
obj = new Object[lowCombo];
array = new int[(numSides * numDice) + 1];
for(int i=0; i < obj.length; i++)
obj[i] = new Die();
// this constructor takes arguments for number of number of dice, die sides,
// and number of lowest side. Trying to be as generic as possible to permit
// inheritance. We assume that all dice are the same for this application.
public Experiment1(int dice, int sides, int low)
numSides = sides;
numDice = dice;
lowCombo = numDice * low;
obj = new Object[lowCombo];
array = new int[(numSides * numDice) + 1];
for(int i=0; i < obj.length; i++)
obj[i] = new Die();
// throws one die 2000 times and saves all the results in an int array
public void runExperiment()
int tally = 0;
for(int i=0; i < 2000; i++)
// this puts the counter for outcome k in the array indexed by k
for(int j=0; j < obj.length; j++)
tally += obj[j].roll();
array[tally]++;
makeBarGraph(array, lowCombo);
The problem is in this line:
tally += obj[j].roll();
but it should work since I have the roll() method defined in the Die() class...
* This class simulates a 6-sided die
* @author Kristian Hermansen
* @version 3/14/2004 (Section 2 Honors)
import java.util.Random;
public class Die
// instance variables
private static Random generator = new Random();
private int num;
* Constructor for objects of class Die
public Die()
// initialise instance variables
num = roll();
* This method simulates a roll
public int roll()
return (generator.nextInt(6) + 1);
public String toString()
return num + "";

Answer 1

Bizarro World Error Message Theory: Error messages, whether from the compiler or the runtime, are not your enemy. They are the friend you know will always be honest with you, even when it hurts. They're telling you something's going wrong. Don't panic. It can be fixed.
The error message will tell you exactly what it can't recognize.