How to sort HashSet in Java
Given a HashSet in Java, the task is to sort this HashSet.
Input: HashSet: [Geeks, For, ForGeeks, GeeksforGeeks] Output: [For, ForGeeks, Geeks, GeeksforGeeks] Input: HashSet: [2, 5, 3, 1, 4] Output: [1, 2, 3, 4, 5]
The HashSet class implements the Set interface, backed by a hash table which is actually a HashMap instance. No guarantee is made as to the iteration order of the set which means that the class does not guarantee the constant order of elements over time.
It means that HashSet does not maintains the order of its elements. Hence sorting of HashSet is not possible.
However, the elements of the HashSet can be sorted indirectly by converting into List or TreeSet, but this will keep the elements in the target type instead of HashSet type.
Below is the implementation of the above approach:
Program 1: By Converting HashSet to List.
Original HashSet: [practice, geeks, contribute, ide] HashSet elements in sorted order using List: [contribute, geeks, ide, practice]
Program 2: By Converting HashSet to TreeSet.
Original HashSet: [practice, geeks, contribute, ide] HashSet elements in sorted order using TreeSet: [contribute, geeks, ide, practice]
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