Java容器 - Collection

• List 按照规则加入list
• Set 加入list中的元素不能重复
• Queue 队列中的元素按照FIFO规则操作

List

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• Positional access — manipulates elements based on their numerical position in -the list. This includes methods such as get, set, add, addAll, and remove.
• Search — searches for a specified object in the list and returns its numerical position. Search methods include indexOf and lastIndexOf.
• Iteration — extends Iterator semantics to take advantage of the list's sequential nature. The listIterator methods provide this behavior.
• Range-view — The sublist method performs arbitrary range operations on the list.

ArrayList

ArrayList存储结构是数组，数组A在申请空间时都是固定大小的，如果A空间不足，就需要重新申请更大的数组B存储数据，然后把A中数据复制到B上。
重新申请arrayB的策略： 按照arrayA的size的一半增加，sizeB = sizeA + sizeA/2。

    private void grow(int minCapacity) {
        // overflow-conscious code
        int oldCapacity = elementData.length;
        int newCapacity = oldCapacity + (oldCapacity >> 1);
        if (newCapacity - minCapacity < 0)
            newCapacity = minCapacity;
        if (newCapacity - MAX_ARRAY_SIZE > 0)
            newCapacity = hugeCapacity(minCapacity);
        // minCapacity is usually close to size, so this is a win:
        elementData = Arrays.copyOf(elementData, newCapacity);
    }

Arrays.copyOf 由 System.arraycopy实现，arraycopy效率涉及到JVM，参考https://www.zhihu.com/question/53749473

LinkedList

根据index查找元素的策略是： 如果index < size/2，从first->last向后遍历，否则从last->first向前遍历。

    Node node(int index) {
        if (index < (size >> 1)) {
            Node x = first;
            for (int i = 0; i < index; i++)
                x = x.next;
            return x;
        } else {
            Node x = last;
            for (int i = size - 1; i > index; i--)
                x = x.prev;
            return x;
        }
    }

Set

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Queue