All of the hashing based Map implementations: HashMap, Hashtable, LinkedHashMap, WeakHashMap and ConcurrentHashMap are modified to use an enhanced hashing algorithm for string keys when the capacity of the hash table has ever grown beyond 512 entries. The enhanced hashing implementation uses the murmur3 hashing algorithm along with random hash seeds and index masks. These enhancements mitigate cases where colliding String hash values could result in a performance bottleneck.
Reviewed-by: alanb, forax, dl
Co-authored-by: Alexander Potochkin <alexander.potochkin@oracle.com>
Co-authored-by: Alexander Zuev <alexander.zuev@oracle.com>
Co-authored-by: Andrew Brygin <andrew.brygin@oracle.com>
Co-authored-by: Artem Ananiev <artem.ananiev@oracle.com>
Co-authored-by: Alex Strange <astrange@apple.com>
Co-authored-by: Bino George <bino@apple.com>
Co-authored-by: Christine Lu <christine.lu@oracle.com>
Co-authored-by: David Katleman <david.katleman@oracle.com>
Co-authored-by: David Durrence <david_durrence@apple.com>
Co-authored-by: Dmitry Cherepanov <dmitry.cherepanov@oracle.com>
Co-authored-by: Greg Lewis <glewis@eyesbeyond.com>
Co-authored-by: Kevin Miller <kevin_m_miller@apple.com>
Co-authored-by: Kurt Miller <kurt@intricatesoftware.com>
Co-authored-by: Landon Fuller <landonf@plausiblelabs.com>
Co-authored-by: Leonid Romanov <leonid.romanov@oracle.com>
Co-authored-by: Loefty Walkowiak <loefty@apple.com>
Co-authored-by: Mark Reinhold <mark.reinhold@oracle.com>
Co-authored-by: Naoto Sato <naoto.sato@oracle.com>
Co-authored-by: Philip Race <philip.race@oracle.com>
Co-authored-by: Roger Hoover <rhoover@apple.com>
Co-authored-by: Scott Kovatch <scott.kovatch@oracle.com>
Co-authored-by: Sergey ByloKhov <sergey.bylokhov@oracle.com>
Co-authored-by: Mike Swingler <swingler@apple.com>
Co-authored-by: Tomas Hurka <tomas.hurka@oracle.com>
Reviewed-by: jjh, alanb, dholmes, anthony, ohrstrom, ksrini, jrose, weijun, smarks
