- 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.
Given a HashSet containing Sport’s name (String), We would like to convert HashSet to Array.
Program – convert HashSet<String> to array (String[]) in java
package org.learn.collection.set.hset;import java.util.Arrays;import java.util.HashSet;import java.util.Set;public class DemoHashSetToArray { public static void main(String[] args) { Set<String> setSports = new HashSet<>(); setSports.add("Tennis"); setSports.add("Cricket"); setSports.add(null); setSports.add("Basketball"); setSports.add(null); setSports.add("Golf"); setSports.add("Boxer"); System.out.println("Set: "+ setSports); String[] hashSetToArray = new String[setSports.size()]; setSports.toArray(hashSetToArray); System.out.println("Array:"+ Arrays.toString(hashSetToArray)); }} |
Output – convert HashSet<String> to array (String[])
Set: [null, Tennis, Cricket, Golf, Basketball, Boxer]Array:[null, Tennis, Cricket, Golf, Basketball, Boxer] |