inflateTable(threshold)

public class Hi {

    //临界值（一个值最接近2的n次幂的数，比如7的临界值为8）

    int threshold;

    //2的30次方，01000000 00000000 00000000 00000000（最大）

    static final int MAXIMUM_CAPACITY = 1 << 30;

    //初始容量为 16（缺省）

    static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16

    //加载因子默认为 0.75

    static final float DEFAULT_LOAD_FACTOR = 0.75f;

    //加载因子

    final float loadFactor;

    //构造函数，初始化时传入了两个值：初始容量和默认加载因子

    public Hi() {

        this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR);

    }

    //构造函数，接收初始容量和加载因子

    public Hi(int initialCapacity, float loadFactor) {

        //如果初始容量小于0，则抛出异常

        if (initialCapacity < 0)

            throw new IllegalArgumentException("Illegal initial capacity: " +

                                               initialCapacity);

        //如果初始容量大于最大容量，则初始容量还是要等于最大限量

        if (initialCapacity > MAXIMUM_CAPACITY)

            initialCapacity = MAXIMUM_CAPACITY;

        //如果加载因子小于0或为空，则抛出异常

        if (loadFactor <= 0 || Float.isNaN(loadFactor))

            throw new IllegalArgumentException("Illegal load factor: " +

                                               loadFactor);

        //赋值类的加载因子属性为传入的加载因子，不传默认为0.75

        this.loadFactor = loadFactor;

        //为临界值赋值，赋值为初始容量16

        threshold = initialCapacity;

        init();

    }

    void init() {

    }

    //提供一个对外的方法，返回值为临界值，用来验证

    public int getSize(){

        //当调用getSize方法时，threshold因为被构造函数赋值，所以此时为16

        System.out.println(threshold);

        //把threshold传入roundUpToPowerOf2，计算临界值

        int size = roundUpToPowerOf2(threshold);

        return size;

    }

     //计算出大于toSize最临近的2的N此方的值

    private static int roundUpToPowerOf2(int number) {

        //稍后分析

        return number >= MAXIMUM_CAPACITY

                ? MAXIMUM_CAPACITY

                : (number > 1) ? Integer.highestOneBit((number - 1) << 1) : 1;

    }

} 

public class Hs {

      public static void main(String []args) {

        Hi hi = new Hi();

        int a = hi.getSize();

        System.out.println(a);

    }

} 

F:\java>java Hs

16

16