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javahashsetlinkedhashset

what's the difference between HashSet and LinkedHashSet

I saw that LinkedHashSet extends HashSet and I know it preserves order.
However, from checking the code in the JDK it seems that LinkedHashSet contains only constuctor and no implementation, so I guess all the logic happens in HashSet?
If that is correct, why is it designed like that? it seems very confusing.

EDIT: there was an unfortunate mistake in the question. I wrote HashMap and LinkedHashMap instead of HashSet and LinkedHashSet. I fixed the question answer it if possible.
Also, I was interested why Java designers chose to implement it like that.

Solution

  • Yes, LinkedHashMap calls its super constructor. One thing it does is to override the init() method, which is called by the super constructor.

    The LinkedHashMap is an HashMap with a doubly-linked list implementation added.