How to convert double[] to List in Java?

Approach 1: By traversing to the elements of array

public static List<Double> getBoxedList_approach1(double[] arr) {
 if (arr == null)
  return null;

 List<Double> result = new ArrayList<>();

 for (double i : arr) {
  result.add(i);

 }
 return result;
}

Approach 2: Using DoubleStream

public static List<Double> getBoxedList_approach2(double[] arr) {
 if (arr == null)
  return null;

 List<Double> result = DoubleStream.of(arr).boxed().collect(Collectors.toList());
 return result;
}

Approach 3: Using Arrays.stream

public static List<Double> getBoxedList_approach3(double[] arr) {
 if (arr == null)
  return null;

 List<Double> result = Arrays.stream(arr).boxed().collect(Collectors.toList());
 return result;
}

App.java

package com.sample.app;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.DoubleStream;

public class App {

 private static void printElements(List<Double> arr) {
  for (double i : arr) {
   System.out.print(i + " ");
  }
  System.out.println();
 }

 public static List<Double> getBoxedList_approach1(double[] arr) {
  if (arr == null)
   return null;

  List<Double> result = new ArrayList<>();

  for (double i : arr) {
   result.add(i);

  }
  return result;
 }

 public static List<Double> getBoxedList_approach2(double[] arr) {
  if (arr == null)
   return null;

  List<Double> result = DoubleStream.of(arr).boxed().collect(Collectors.toList());
  return result;
 }

 public static List<Double> getBoxedList_approach3(double[] arr) {
  if (arr == null)
   return null;

  List<Double> result = Arrays.stream(arr).boxed().collect(Collectors.toList());
  return result;
 }

 public static void main(String args[]) throws IOException {
  double[] arr = { 1.1, 3.3, 5.5, 7, 2, 4, 6, 8, 10 };

  List<Double> result1 = getBoxedList_approach1(arr);
  printElements(result1);

  List<Double> result2 = getBoxedList_approach2(arr);
  printElements(result2);

  List<Double> result3 = getBoxedList_approach3(arr);
  printElements(result3);

 }
}

Output

1.1 3.3 5.5 7.0 2.0 4.0 6.0 8.0 10.0

1.1 3.3 5.5 7.0 2.0 4.0 6.0 8.0 10.0

1.1 3.3 5.5 7.0 2.0 4.0 6.0 8.0 10.0

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