The jdk's discuss from zxiaofan

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Source code for multiple JDK versions(1.6/1.7/1.8/1.9/10/11/12/13/14/15/16/17/18 JDK's src.zip), Only for learning; "rt_debug.jar" can be used for debugging.

License: Apache License 2.0

jdk's Issues

jdk6

把jdk6的也放进来吧, 这样就全了.

ConcurrentHashMap源码问题

在CSDN上看到博主的文章，想问下关于ConcurrentHashMap的问题，望解答哈

    private final void tryPresize(int size) {
        int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
            tableSizeFor(size + (size >>> 1) + 1);
        int sc;
        while ((sc = sizeCtl) >= 0) {
            Node<K,V>[] tab = table; int n;
            if (tab == null || (n = tab.length) == 0) {
                n = (sc > c) ? sc : c;
                if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
                    try {
                        if (table == tab) {
                            @SuppressWarnings("unchecked")
                            Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
                            table = nt;
                            sc = n - (n >>> 2);
                        }
                    } finally {
                        sizeCtl = sc;
                    }
                }
            }
            else if (c <= sc || n >= MAXIMUM_CAPACITY)
                break;
            else if (tab == table) {
                int rs = resizeStamp(n);
                if (sc < 0) {
                    Node<K,V>[] nt;
                    if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
                        sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
                        transferIndex <= 0)
                        break;
                    if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
                        transfer(tab, nt);
                }
                else if (U.compareAndSwapInt(this, SIZECTL, sc,
                                             (rs << RESIZE_STAMP_SHIFT) + 2))
                    transfer(tab, null);
            }
        }
    }

我的问题是，上面这段代码的sc < 0可能吗？百思不得其解啊

                if (sc < 0) {
                    Node<K,V>[] nt;
                    if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
                        sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
                        transferIndex <= 0)
                        break;
                    if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
                        transfer(tab, nt);
                }

源码来源问题（1.7的HashMap源码与网上各种博客里的源码不一致）

HashMap(int initialCapacity, float loadFactor)构造方法源码区别：
本仓库：threshold = (int)Math.min(capacity * loadFactor, MAXIMUM_CAPACITY + 1);
网上博客里的：threshold = initialCapacity;

另外还有很明显的地方是，本仓库中1.7的HashMap源码中没有inflateTable方法。

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