HashTable has these tunable parameters:
Capacity (usually a prime number), initialCapacity; if this is not set large enough, collisions will result, causing hashing to stop and linear list processing to be executed afterwards.
Load factor (0.0-1.0), loadFactor, which is a percentage of capacity beyond which the table will expand. HashTable calls hashCode(). These classes have pre-defined hashCode() methods:
Color, Font, Point
File
Boolean, Byte, Character, Double, Float, Integer, Long, Short, String
URL
BitSet, Date, GregorianCalendar, Locale, SimpleTimeZone. Note that String.hashCode() does not always sample all the characters, depending on the length:
Length from 1 to 15: all n Length from 16 to 23: every other character
Length from 24 to 31: every third character
And so on.