Convert LinkedHashSet to Array in Java Example

This example shows how to convert LinkedHashSet to an array in Java. This example also shows how to convert LinkedHashSet to an array using the toArray method and Java 8 Stream.

How to convert LinkedHashSet to an array in Java?

There are a couple of ways using which we can convert LinkedHashSet object to an array as given below.

1. Using the toArray method

We can use the toArray method of the LinkedHashSet class to convert to an array.

1	<T> T[] toArray(T[] a)

The toArray method returns an array containing all the elements of this linked hash set object. Since the LinkedHashSet iterator guarantees the element order, the order of the array elements is the same as the insertion order in the LinkedHashSet.

import java.util.LinkedHashSet;

import java.util.Set;

public class LinkedHashSetToArrayExample {

public static void main(String[] args) {

Set<String> lhSetColors = new LinkedHashSet<String>();

lhSetColors.add("red");

lhSetColors.add("green");

lhSetColors.add("blue");

lhSetColors.add("white");

lhSetColors.add("black");

//create new array of same type and same size

String[] strColors = new String[ lhSetColors.size() ];

//convert using the toArray method

strColors = lhSetColors.toArray(strColors);

System.out.println("Array contains:");

for(String strColor : strColors){

System.out.println(strColor);

}

Output

Array contains:

red

green

blue

white

black

Important Note:

If the array specified in the toArray method is large enough to hold all elements of the LinkedHashSet object, the same array is filled with the elements and returned. If the specified array is smaller than the linked hash set object, a new array is allocated, filled with the set elements and then returned.

Always make sure that the array is at least equal to the size of the LinkedHashSet object to avoid the costly operation of a new array allocation.

If the specified array is bigger than the linked hash set object, the element that comes immediately after the linked hash set elements is set to null to indicate the end of the set elements as shown below.