Program to convert Array to List and Set in Java

There are following way to convert Array to List and Set in Java.

Convert Array to Set :-

The set interface is an unordered collection of objects in which duplicate values cannot be stored.
In first way, we pass the Array as parameter in the set constructor with the help of Arrays.asList () method.
Return String type set and print the data.
In Second way, we are stream the Array data from Arrays.asList() method then convert in set from Collectors.toSet() method.
Return String type set and print the data.

				
					import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.stream.Collectors;

public class ConvertArrayToSet {
	public static void main(String[] args) {
		String s[] = { "java", "Spring", "Hibernate", "java" };
		
		// from Arrays.asList method
		Set<String> st = new HashSet<String>(Arrays.asList(s));
		System.out.println("Arrays.asList method output :- " + st);
		
		Set<String> data = Arrays.asList(s).stream().collect(Collectors.toSet());
		System.out.println("from java 8 list method value :- " + data);
	}
}

Output :-
Arrays.asList method output :- [Hibernate, java, Spring]
from java 8 list method value :- [Hibernate, java, Spring]

Convert Array to List :-

The List interface is an unordered collection of objects in which duplicate values can be stored.
In First Way, we convert Array to list from asList() method because it is internally call new ArrayList() class.

Syntax:- public static <T> List<T> asList(T… a) { return new ArrayList<>(a); }

Return String type set and print the data.
In Second way, we create one empty ArrayList Object.
From forEach() method we iterate Array data one by one and add to list.
Return String type set and print data.
In Third way, we are stream the Array data from Arrays.asList() method then convert in List from toList() method.
Return String type List and print the data.

				
					import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class ConvertArrayToList {
	public static void main(String[] args) {
		String s[] = { "java", "Spring", "Hibernate", "java" };
		
		// first way from Arrays.asList method
		List<String> list = Arrays.asList(s);
		System.out.println("Arrays.asList method output :- " + list);
		
		// second way from forEach and list add method
		List<String> addList = new ArrayList<String>();
		for (String st : s) {
			addList.add(st);
		}
		System.out.println("from forEach and list add method :- " + addList);
		
		// third way from java8 list method
		List<String> data = Arrays.asList(s).stream().collect(Collectors.toList());
		System.out.println("from java 8 list method value :- " + data);

	}
}

Output :-
Arrays.asList method output :- [java, Spring, Hibernate, java]
from forEach and list add method :- [java, Spring, Hibernate, java]
from java 8 list method value :- [java, Spring, Hibernate, java]