How to convert primitive Array to List & Vice versa

Hello friends,

I am going to explain very easy and basic topic “How to convert primitive Array to List”.

so i have provided both way before java8 and in java8

1.before java8, we can create list object and using for each loop can add all elements in list.

2 and using Java8, can use IntStream.of or Arrays.stream.

package com.neesri.array;

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

public class ConvertArrayinList {

 public static void main(String[] args) {

  int primitiveArray[] = { 2, 6, 4, 3, 2, 8 };
  
  // 1. primitive array to arrayList before JAVA 8
  List<Integer> primitiveList = convertPrimitiveArraysIntoList(primitiveArray);
  System.out.println("Converting primitve int array to ArrayList--> " + primitiveList);

  // 1. primitive array to arrayList in JAVA 8, 
  // can use IntStream.of or Arrays.stream, same output

 // List<Integer> list = Arrays.stream(primitiveArray).boxed().collect(Collectors.toList());
  List<Integer> list = IntStream.of(primitiveArray).boxed().collect(Collectors.toList());

  System.out.println("converting PrimitveArray to List in java8 ---> " + list);
 }

 private static List<Integer> convertPrimitiveArraysIntoList(int[] primitivearray) {
  List<Integer> list_primitive = new ArrayList<>();
  for (int i : primitivearray) {
   list_primitive.add(i);

  }
  return list_primitive;

 }

}

Convert List to int Array :-

  
  // Convert List to int Array 
  
   List<Integer> list1 = Arrays.asList(1, 2, 3, 4, 5);
   
      int[] primitive = list1.stream()
                          .mapToInt(Integer::intValue)
                          .toArray();

      System.out.println("Convert List to int Array---> "
       +Arrays.toString(primitive));

Thanks and Happy Learning :)