Constants read by reflection from the running JDK's own HashMap and ConcurrentHashMap
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runtime: 25.0.5+8-LTS (Eclipse Adoptium)

java.util.HashMap
  DEFAULT_INITIAL_CAPACITY   = 16
  MAXIMUM_CAPACITY           = 1073741824
  DEFAULT_LOAD_FACTOR        = 0.75
  TREEIFY_THRESHOLD          = 8
  UNTREEIFY_THRESHOLD        = 6
  MIN_TREEIFY_CAPACITY       = 64

java.util.concurrent.ConcurrentHashMap
  DEFAULT_CAPACITY           = 16
  MAXIMUM_CAPACITY           = 1073741824
  LOAD_FACTOR                = 0.75
  DEFAULT_CONCURRENCY_LEVEL  = 16
  TREEIFY_THRESHOLD          = 8
  UNTREEIFY_THRESHOLD        = 6
  MIN_TREEIFY_CAPACITY       = 64
  MIN_TRANSFER_STRIDE        = 16
  RESIZE_STAMP_BITS          = 16
  RESIZE_STAMP_SHIFT         = 16
  MAX_RESIZERS               = 65535
  MOVED                      = -1
  TREEBIN                    = -2
  RESERVED                   = -3
  HASH_BITS                  = 2147483647