Convert HashSet to TreeSet in java (example)

What is HashSet in java?

  • HashSet class implements the Set interface, backed by a hash table.
  • HashSet contains the unique elements.
    • HashSet does not contains any duplicate keys
    • HashSet can have only 1 null key.
  • HashSet does not maintained the order of elements or keys.
  • HashSet is UnSynchronized and not thread safe.

Program – Convert HashSet<String> to TreeSet<String>

package org.learn.collection.set.hset;

import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

public class DemoHashSetToTreeSet {

 public static void main(String[] args) {
  Set<String> setSports = new HashSet<>();
  setSports.add("Tennis");
  setSports.add("Cricket");
  setSports.add("Tennis");
  setSports.add("Basketball");
  setSports.add("Golf");
  setSports.add("Boxer");  
  
  System.out.println("Set: "+ setSports);
  
  Set<String> hashSetToTreeSet = new TreeSet<>(setSports);
  System.out.println("TreeSet:"+hashSetToTreeSet);  
 }
}

Output – convert HashSet to TreeSet in java

Set: [Tennis, Cricket, Golf, Basketball, Boxer]
TreeSet:[Basketball, Boxer, Cricket, Golf, Tennis]
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