RFR 8005698 : Handle Frequent HashMap Collisions with Balanced Trees (original) (raw)

Brent Christian brent.christian at oracle.com
Mon Jun 3 23:34:17 UTC 2013

Hi, Paul

If a HashMap is created via serialization or clone(), we don't check if the table needs resizing when adding entries, but still need to check if a bin should be converted to a TreeBin. In this case, putForCreate() calls createEntry() directly, instead of addEntry().

Thanks, -Brent

On 6/3/13 12:56 AM, Paul Sandoz wrote:

Hi Brent,

A minor thing: take it or leave it :-) In HashMap: 2207 void addEntry(int hash, K key, V value, int bucketIndex, boolean checkIfNeedTree) { 2208 // assert key != null; 2209 if ((size >= threshold) && (null != table[bucketIndex])) { 2210 resize(2 * table.length); 2211 hash = hash(key); 2212 bucketIndex = indexFor(hash, table.length); 2213 } 2214 createEntry(hash, key, value, bucketIndex, checkIfNeedTree); 2215 } You could re-verify the bucket size if the table is resized rather than in createEntry, since that AFAICT is the only case where conditions after the call to addEntry might change. Pau.

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