Method resize

java/05_array/GenericArray.java:143–150

(int capacity)

    // 扩容方法，时间复杂度 O(n)
    private void resize(int capacity) {
        T[] newData = (T[]) new Object[capacity];

        for (int i = 0; i < size; i++) {
            newData[i] = data[i];
        }
        data = newData;
    }

    private void checkIndex(int index) {
        if (index < 0 || index >= size) {