The package java.util.* does not contain the class ArrayQueue. It is found in another package. Either you import that package through the jar file or implement the class ArrayQueue.

ArrayQueue.java:

class ArrayQueue implements Queue 
{

    static final int defaultsize = 100;

    Object data[];
    int head;
    int tail;
    int size;

    ArrayQueue(int maxsize) 
    {
        data = new Object[maxsize];
        head = 0;
        tail = 0;
        size = maxsize;
    }

    ArrayQueue() 
    {
        data = new Object[defaultsize];
        head = 0;
        tail = 0;
        size = defaultsize;
    }

    public void enqueue(Object elem) 
    {
    Assert.notFalse((tail+1)%size != head, "Queue Full");
    data[tail] = elem;
    tail = (tail + 1) % size;
    }

    public Object dequeue() 
    {
    Object retval;

    if (head == tail)
        return null;
    retval = data[head];
    head = (head + 1) % size;
    return retval;
    }

    public boolean empty() 
    {
    return head == tail;
    }

    public String toString()
    {
    String result = "[";
        int tmpHead = head;
    if (tmpHead != tail)
    {
            result = result + data[tmpHead];
            tmpHead = (tmpHead + 1) % size;
            while (tmpHead != tail)
            {
        result = result + "," + data[tmpHead];
                tmpHead = (tmpHead + 1) % size;
        }
    }
    result = result + "]";
    return result;
    }

}