Java Program to Convert the ArrayList into a string and vice versa

In this article, we will understand how to convert the arrayList into a string and vice versa. The ArrayList class is a resizable array, which can be found in the java. util package. The difference between a built-in array and an ArrayList in Java, is that the size of an array cannot be modified.

Below is a demonstration of the same −

Suppose our input is −

Input string: Java Program

The desired output would be −

The array after conversion from string is:
J a v a P r o g r a m

Algorithm

Step 1 - START
Step 2 - Declare namely
Step 3 - Define the values.
Step 4 - Create an array and add elements to it using the ‘add’ method.
Step 5 - Display the list on the console.
Step 6 - Create another empty array of previous array size.
Step 7 - Convert it into string using the ‘toString’ method.
Step 8 - Iterate over the elements and display the elements on the console.
Step 9 - Stop

Example 1

import java.util.ArrayList;
public class Demo {
   public static void main(String[] args) {
      System.out.println("The required packages have been imported");
      ArrayList input_array= new ArrayList<>();
      input_array.add("Java");
      input_array.add("Python");
      input_array.add("Scala");
      input_array.add("JavaScript");
      System.out.println("The array is defined as: " + input_array);
      String result_string = input_array.toString();
      System.out.println("\nThe result string is: " + result_string);
   }
}

Output

The required packages have been imported
The array is defined as: [Java, Python, Scala, JavaScript]

The result string is: [Java, Python, Scala, JavaScript]

Example 2

Here, we convert a string to an array.

public class Demo {
   public static void main(String args[]){
      String input_string = "Java Program";
      System.out.println("The string is defined as: " + input_string);
      char[] result_array = new char[input_string.length()];
      for (int i = 0; i < input_string.length(); i++) {
         result_array[i] = input_string.charAt(i);
      }
      System.out.println("The array after conversion from string is: " );
      for (char c : result_array) {
         System.out.print(c + " ");
      }
   }
}

Output

The string is defined as: Java Program
The array after conversion from string is:
J a v a  P r o g r a m