A little problem with collections

aaronkoo

Use the same data BEAN (an INT, a STRING, did not implement EQUALS () and HASHCODE ()), which implemented the compareTo () method in Comparable, and then added to HASHSET and TREESET respectively, why can be automatically in TREESET Two objects with the same ordering and status cannot be added to the TreeSet collection at the same time, but not in HASHSET.

ghxy913

The HashSet, HashTable and the HashMap are based on the HasCode ().

aaronkoo

Yesterday I checked the information, just like Haiyan (the same name as my previous MM, huh) except TREESET, you must implement the data BEAN EQUALS () and HASHCODE () ...

ghxy913

:)