Java ArrayList.toArray(T[] a)() Method

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

The toArray() method is used to get an array which contains all the elements in ArrayList object in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array.
If the list fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this list.

Package: java.util

Java Platform: Java SE 8

Syntax:

toArray(T[] a)

Type Parameters: T - the runtime type of the array to contain the collection

Parameters:

Return Value:
An array containing the elements of the list

Throws:

• ArrayStoreException - if the runtime type of the specified array is not a supertype of the runtime type of every element in this list
• NullPointerException - if the specified array is null

Pictorial presentation of ArrayList.toArray(T[] a) Method

Example: ArrayList.toArray(T[] a) Method

The following example shows the usage of java.util.Arraylist.toArray(T[] a)() method method.

import java.util.*;

public class test {
   public static void main(String[] args) {
      
    // create an empty array list with an initial capacity
    ArrayList<String> color_list = new ArrayList<String>(5);

    // use add() method to add values in the list
    color_list.add("White");
    color_list.add("Black");
    color_list.add("Red");
    color_list.add("White");
	color_list.add("Yellow");
	
    System.out.println("Size of the color_list: " + color_list.size());

    // Print the colors in the list
    for (String value : color_list){
      System.out.println("Color = " + value);
    }  
   // Create an array from the ArrayList
    String color_list2[] = new String[color_list.size()];
    color_list2 = color_list.toArray(color_list2);
         
   // Display the contents of the array
    System.out.println("Printing elements of color_list2:"); 
    for (String color : color_list2) {
      System.out.println("Color = " + color);
    }
  }
}
   

Output:

F:\java>javac test.java
F:\java>java test
Size of the color_list: 5
Color = White
Color = Black
Color = Red
Color = White
Color = Yellow
Printing elements of color_list2:
Color = White
Color = Black
Color = Red
Color = White
Color = Yellow

Java Code Editor:

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