Java中的Map

public HashMap(int initialCapacity, float loadFactor) {
　　　　　// initialCapacity代表初始化HashMap的容量，它的最大容量是MAXIMUM_CAPACITY = 1 << 30。
        if (initialCapacity < 0)
            throw new IllegalArgumentException("Illegal initial capacity: " +
                                               initialCapacity);
        if (initialCapacity > MAXIMUM_CAPACITY)
            initialCapacity = MAXIMUM_CAPACITY;

　　　　 // loadFactor代表它的负载因子，默认是是DEFAULT_LOAD_FACTOR=0.75，用来计算threshold临界值的。
        if (loadFactor <= 0 || Float.isNaN(loadFactor))
            throw new IllegalArgumentException("Illegal load factor: " +
                                               loadFactor);

        // Find a power of 2 >= initialCapacity
        int capacity = 1;
        while (capacity < initialCapacity)
            capacity <<= 1;

        this.loadFactor = loadFactor;
        threshold = (int)(capacity * loadFactor);
        table = new Entry[capacity];//创建数组
        init();
    }