CopyOnWriteArrayList 源码分析 - 删除

public E remove(int index) {    final ReentrantLock lock = this.lock;    lock.lock();    try {        Object[] elements = getArray();        int len = elements.length;        E oldValue = get(elements, index);        int numMoved = len - index - 1;        if (numMoved == 0)            setArray(Arrays.copyOf(elements, len - 1));        else {            Object[] newElements = new Object[len - 1];            System.arraycopy(elements, 0, newElements, 0, index);            System.arraycopy(elements, index + 1, newElements, index,                             numMoved);            setArray(newElements);        }        return oldValue;    } finally {        lock.unlock();    }}

public boolean removeAll(Collection<?> c) {    if (c == null) throw new NullPointerException();    final ReentrantLock lock = this.lock;    lock.lock();    try {        Object[] elements = getArray();        int len = elements.length;        if (len != 0) {            int newlen = 0;            Object[] temp = new Object[len];            for (int i = 0; i < len; ++i) {                Object element = elements[i];                if (!c.contains(element))                    temp[newlen++] = element;            }            if (newlen != len) {                setArray(Arrays.copyOf(temp, newlen));                return true;            }        }        return false;    } finally {        lock.unlock();    }}