Convert an Array to ArrayList in Java with Example

In this tutorial, I am sharing how to convert an Array to ArrayList in Java with examples. I have already shared the difference between Array and ArrayList in Java. Also in the last tutorial I have shared the three methods of converting an ArrayList to Array in Java with example. There are three ways to achieve our goal of converting an Array to ArrayList:

1. Using Arrays class asList() method

2. Using Collections class addAll() method

3. Using add() method

Convert an Array to ArrayList in Java

Method 1 : Using Arrays.asList() method

In this example, we are converting an Array to ArrayList using Arrays class asList() method. The syntax is given below:

Syntax :

 ArrayList<String> list = new ArrayList<>(Arrays.asList(arrayname));

import java.util.*;

public class ConvertArrayToArrayList {
    public static void main(String args[]) {
      // Declaring and initializing Array
      String[] cities={"Boston", "Dallas", "New York", "Chicago"};

      //Converting Array to ArrayList using Arrays.asList()
      ArrayList<String> list= new ArrayList<>(Arrays.asList(cities));
      
      // Add more elements to the converted list
      list.add("San Francisco");
      list.add("San jose");
      
      // Print arraylist elements using for-each loop
      for(String s : list) {
        System.out.println(s);      
      }
    }
}

Output:

Boston
Dallas
New York
Chicago
San Francisco
San jose

Method 2 : Using Collections.addAll() method

This method does the same as Arrays.asList() method however it is much faster hence performance wise this is the best way to convert Array to ArrayList. The syntax for the addAll() method is given below:

Syntax:

 Collections.addAll(arraylist, array);

import java.util.*;

public class ConvertArrayToArrayList2 {
    public static void main(String args[]) {
      // Creating and initializing Array
      String[] strArray = {"AAA", "BBB", "CCC", "DDD"};
      
      // Declaring ArrayList
      ArrayList<String> al = new ArrayList<>();

      //Converting Array to ArrayList using addAll() method
      Collections.addAll(al, strArray);
      
      // Add more elements to the converted list
      al.add("YYY");
      al.add("ZZZ");
      
      // Displaying arraylist elements using for-each loop
      for(String s : al) {
        System.out.println(s);      
      }
    }
}

Output:

AAA
BBB
CCC
DDD
YYY
ZZZ

Method 3 : Using add() method

If we don't want to use java built-in methods then we can use add() method to convert an array to ArrayList. This is a manual way of adding all the array elements to the ArrayList as shown below:

import java.util.*;

public class ConvertArrayToArrayList3 {
    public static void main(String args[]) {
      // Declaring and instantiating ArrayList in one step
      ArrayList<String> al = new ArrayList();
      
      // Given initialized array 
      String[] strArray = {"Cocacola", "Pepsi", "Fanta", "Dr Pepper"};
      
      //Converting Array to ArrayList manually
      for (int i=0; i < strArray.length ; i++) {
          // Adding every element of array to the ArrayList  
          al.add(strArray[i]);
      }
      
      // Showing arraylist elements using for-each loop
      for(String str1 : al) {
        System.out.println(str1);      
      }
    }
}

Output:

Cocacola
Pepsi
Fanta
Dr Pepper

That's all for today. Please mention in the comments if you have any questions related to how to convert an array to ArrayList in Java with examples.

Java Hungry

Convert an Array to ArrayList in Java with Example