In this tutorial we will learn about java set to list conversion . In Order to convert set to list in Java , We have couple of method . We Knew that ArrayList In Java is a ordered collection and allow duplicate element . But TreeSet in Java is avoids duplicates. Let’s see how to convert set to list in java using different approaches .
Convert Set to List In Java
We will discuss different method for converting set to list in java . We can convert set to list in java using below method
1. Java Set to List Using ArrayList or LinkedList Constructor
In this example we will create a set of Strings and add some elements in it using add() method.Now we will initialize ArrayList Using Parameterized Constructor with Set elements .
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
public class SetToList {
public static void main(String[] args) {
//create HashSet
Set<String> set = new TreeSet<String>();
//add element into Set using add() method
set.add("Java");
set.add("Vogue");
set.add("Welcomes");
// print Set
System.out.println("Set Elements : " + set);
// create list from set
List<String> list = new ArrayList<String>(set);
// print element of list
for (String element : list) {
System.out.println("List Element is : " + element);
}
}
}
Output:
Set Elements : [Java, Vogue, Welcomes]
List Element is : Java
List Element is : Vogue
List Element is : Welcomes
2. Convert Set to List Using AddAll() Method
In this example we will convert Set to ArrayList using addAll() method of List . Firstly we created Set of Strings and then add some element into it using add() method . Now we will create list, then add Set elements to it using List’s addAll() method .
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
public class SetToList1 {
public static void main(String[] args) {
// create HashSet
Set<String> set = new TreeSet<String>();
// add element into Set using add() method
set.add("Java");
set.add("Vogue");
set.add("Welcomes");
// print Set
System.out.println("Set Elements : " + set);
// create list from set
List<String> list = new ArrayList<String>();
////adding set elements to the list using the addAll() method
list.addAll(set);
// print element of list
for (String element : list) {
System.out.println("List Element is : " + element);
}
}
}
Output:
Set Elements : [Java, Vogue, Welcomes]
List Element is : Java
List Element is : Vogue
List Element is : Welcomes
3. Convert Set to List Using add() Method
In this approach,we will convert Set to List in java using for loop . We create Set and add elements into it. We also created one list. Now We Iterate Set element Using for-each loop and one by one element of Set will added to list using add() method . Let,s see java program for this approach.
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
public class SetToList2 {
public static void main(String[] args) {
// create HashSet
Set<String> set = new TreeSet<String>();
// add element into Set using add() method
set.add("Java");
set.add("Vogue");
set.add("Welcomes");
// print Set
System.out.println("Set Elements : " + set);
// create list from set
List<String> list = new ArrayList<String>();
for (String element : set) {
//adds element to list
list.add(element);
}
System.out.println("List Elements : "+ list);
}
}
Output:
Set Elements : [Java, Vogue, Welcomes]
List Elements : [Java, Vogue, Welcomes]
In this tutorial we have learned java set to list conversion . We have can convert set to LinkedList in java using same above methods for convert set to arraylist in java . you can see more good java TreeSet program for practice .
Reference :