How to implement a Queue
This example shows how to implement a Queue in Java easily.
import java.util.LinkedList;

class Queue {
private LinkedList queue;

public Queue() {
queue = new LinkedList();
}

public void add(T obj) {
queue.add(obj);
}

public void removeFirst() {
queue.removeFirst();
}

public int size() {
return queue.size();
}
}
Note: if multiple threads can access the queue, the inner LinkedList should be synhronized: queue = (LinkedList) Collections.synchronizedList(queue)