ArrayList 扩容时如何出现内存溢出的情况

Question

public boolean add(E e) {
ensureCapacityInternal(size + 1);
elementData[size++] = e;
return true;
}

private void ensureCapacityInternal(int minCapacity) {
    if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA) {
        minCapacity = Math.max(DEFAULT_CAPACITY, minCapacity); 
    }
    ensureExplicitCapacity(minCapacity);
}

private void ensureExplicitCapacity(int minCapacity) {
    modCount++;
    if (minCapacity - elementData.length > 0)
        grow(minCapacity);
}

private void grow(int minCapacity) {
    int oldCapacity = elementData.length; 
    int newCapacity = oldCapacity + (oldCapacity >> 1);
    if (newCapacity - minCapacity < 0) 
                    newCapacity = minCapacity;
    if (newCapacity - MAX_ARRAY_SIZE > 0) 
        newCapacity = hugeCapacity(minCapacity);
    elementData = Arrays.copyOf(elementData, newCapacity);
}

private static int hugeCapacity(int minCapacity) {
    if (minCapacity < 0)
        throw new OutOfMemoryError();
    return (minCapacity > MAX_ARRAY_SIZE) ?
            Integer.MAX_VALUE :
            MAX_ARRAY_SIZE;
}

这里传入的minCapacity什么情况下会出现小于0的情况？还请赐教。

Answer 1

int minCapacity，是有符号的int，要考虑溢出的问题
如果它大于2147483647，那么就会变成负数。