Blocking Queue implementation

BlockingQueue.java

import java.util.*;

public class BlockingQueue<T> {
    private Queue<T> queue = new LinkedList<T>();
    private int capacity = 10; //default capacity is 10

    BlockingQueue() {}
    BlockingQueue(int capacity) {
        this.capacity = capacity;
    }

    // add element at the end of the queue
    public synchronized void add(T elem) throws InterruptedException {
        while(queue.size() == capacity) {
            wait();
        }
        queue.add(elem);
        if(queue.size() == 1) {
            notifyAll();
        }
    }

    // removes first element in the queue
    public synchronized T remove() throws InterruptedException {
        while(queue.size() == 0) {
            wait();
        }
        if(queue.size() == capacity) {
            notifyAll();
        }
        T removedElement = queue.remove();
        return removedElement;
    }
}