Why won't it compile?

Question

I have four classes. I have been told that i can compile the main one and the rest will compile by them selves. This doesn't seem to work. I can't even compile then seperatley. Any ideas why they won't work?
Main Code;
public class TestBoundedBuffer {
public static void main(String args[] ) {
// just create the two threads and the bounded buffer
BoundedBuffer b = new BoundedBuffer();
ProduceIntegers p = new ProduceIntegers(b);
ConsumeIntegers c = new ConsumeIntegers(b);
p.start();
c.start();
THREE OTHER CLASSES:
public class BoundedBuffer {
private static final int BUFFER_SIZE = 5;
private int count, in, out;
private int [] buffer;
public BoundedBuffer() {
count = 0;
in = 0;
out = 0;
buffer = new int[BUFFER_SIZE];
public synchronized void enter(int item) {
while (count == BUFFER_SIZE) {
try {
wait();
     catch (InterruptedException e) { }
// add an item to the buffer
count++;
buffer[in] = item;
in = (in + 1) % BUFFER_SIZE;
notify();
public synchronized int remove() {
int item;
while (count == 0) {
try {
wait();
     catch (InterruptedException e) { }
// Remove an item from the buffer
count--;
item = buffer[out];
out = (out + 1) % BUFFER_SIZE;
notify();
return item;
NEXT CLASS:
public class ProduceIntegers extends Thread {
private BoundedBuffer buff;
public ProduceIntegers( BoundedBuffer b ) {
buff = b;
public void run() {
for (int i=0; i<100; i++) {
System.out.println("Produced " + i);
buff.enter(i);
NEXT CLASS:
public class ConsumeIntegers extends Thread {
private BoundedBuffer buff;
public ConsumeIntegers( BoundedBuffer b ) {
buff = b;
public void run() {
for (int i=0; i<100; i++) {
int item = buff.remove();
System.out.println( "Consumed " + item);

Answer 1

1) each of the 4 classes needs to be written in their own .java file, and in the same directory as the main .java file
or
2) TestBoundedBuffer.java can contain all the code for the other 3 classes, but you have to remove "public" as the class accessor.
ie
public class ProduceIntegers extends Thread {
becomes
class ProduceIntegers extends Thread {