static class Entry extends WeakReference<ThreadLocal<?>> {
            Object value;
            Entry(ThreadLocal<?> k, Object v) {
                super(k);
                value = v;
            }
        }
        //初始容量16
        private static final int INITIAL_CAPACITY = 16;
        //散列表
        private Entry[] table;
        //entry 有效數(shù)量 
        private int size = 0;
        //負(fù)載因子
        private int threshold; 

    private void set(ThreadLocal<?> key, Object value) {
            Entry[] tab = table;
            int len = tab.length;
            //與運(yùn)算  & (len-1) 這就是為什么 要求數(shù)組len 要求2的n次冪 
            //因?yàn)閘en減一后最后一個(gè)bit是1 與運(yùn)算計(jì)算出來的數(shù)值下標(biāo) 能保證全覆蓋 
            //否者數(shù)組有效位會(huì)減半 
            //如果是hashmap 計(jì)算完下標(biāo)后 會(huì)增加鏈表 或紅黑樹的查找計(jì)算量 
            int i = key.threadLocalHashCode & (len-1);
            // 從下標(biāo)位置開始向后循環(huán)搜索  不會(huì)死循環(huán)  有擴(kuò)容因子 必定有空余槽點(diǎn)
            for (Entry e = tab[i];   e != null;  e = tab[i = nextIndex(i, len)]) {
                ThreadLocal<?> k = e.get();
                //一種情況 是當(dāng)前引用 返回值
                if (k == key) {
                    e.value = value;
                    return;
                }
                //槽點(diǎn)被GC掉 重設(shè)狀態(tài) 
                if (k == null) {
                    replaceStaleEntry(key, value, i);
                    return;
                }
            }
			//槽點(diǎn)為空 設(shè)置value
            tab[i] = new Entry(key, value);
            //設(shè)置ThreadLocal數(shù)量
            int sz = ++size;
			//沒有可清理的槽點(diǎn) 并且數(shù)量大于負(fù)載因子 rehash
            if (!cleanSomeSlots(i, sz) && sz >= threshold)
                rehash();
        }

    public void set(T value) {
        Thread t = Thread.currentThread();
        ThreadLocalMap map = getMap(t);
        if (map != null)
            map.set(this, value);
        else
            **createMap**(t, value);
    }
    void createMap(Thread t, T firstValue) {
        t.threadLocals = **new ThreadLocalMap**(this, firstValue);
    }

void createMap(Thread t, T firstValue) {
        t.inheritableThreadLocals = new ThreadLocalMap(this, firstValue);
    }