How to initialize HashSet in java
We have many ways to initialize HashSet in java.
HashSet can be initialized in one line, Using constructors, Using Arrays.
1. Initialize HashSet using Constructors
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | package com.kscodes.sampleproject; import java.util.HashSet; import java.util.Set; public class HashSetInitalize { public static void main(String[] args) { Set<String> hashSet = new HashSet<>(); hashSet.add("Java"); hashSet.add("Spring"); hashSet.add("Hibernate"); hashSet.add("JavaScript"); System.out.println(hashSet.toString()); } } |
2. Initialize HashSet in One line using Arrays.asList()
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | package com.kscodes.sampleproject; import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class HashSetInitalize { public static void main(String[] args) { Set<String> hashSet = new HashSet<>(Arrays.asList("Java", "JSP", "JavaScript", "JQuery")); System.out.println(hashSet.toString()); } } |
3. Initialize HashSet using Collections (Another List)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | package com.kscodes.sampleproject; import java.util.ArrayList; import java.util.Arrays; import java.util.HashSet; import java.util.List; import java.util.Set; public class HashSetInitalize { public static void main(String[] args) { List<String> arrList1 = new ArrayList<>(Arrays.asList("Java","JSP","JavaScript","JQuery")); Set<String> hashSet = new HashSet<>(arrList1); System.out.println(hashSet.toString()); } } |