Convert Array to ArrayList in Java

This Java Example shows how to convert an array to Java ArrayList object using Arrays.asList method.

import java.util.Arrays;
import java.util.List;

public class ConvertArrayToArrayListExample {

 public static void main(String[] args) {

  String[] countries = { "India", "Switzerland", "Italy", "France" };

  /**
   * List asList(Object[] a) - Returns a fixed-size list backed by the
   * specified array(Changes to the returned list "write through" to the
   * array).Operations such as add,remove which affects the list size
   * can't be performed on the returned list;which throws
   * java.lang.UnsupportedOperationException.
   **/

  List list = Arrays.asList(countries);

  System.out.println("List contains...");

  // display elements of List

  for (int index = 0; index < list.size(); index++)
   System.out.println(list.get(index));

  System.out.println("Replace an element in the returned list.");

  /** Works perfectly.set won't affect the returned list size **/

  list.set(1, "America");
  System.out
    .println("After replacing 'Switzerland' with 'America'.Array contains...");

  /**
   * Notice that changes to the returned list will also be reflected in
   * the array.
   **/

  for (String c : countries) {
   System.out.println(c);
  }

  System.out.println("Add an element in the returned list.");

  /**
   * try to change size of the returned list, throws
   * UnsupportedOperationException
   **/
  list.add("Canada");

 }
}

The output is :



List contains...
India
Switzerland
Italy
France
Replace an element in the returned list.
After replacing 'Switzerland' with 'America'.Array contains...
India
America
Italy
France
Add an element in the returned list.
Exception in thread "main" java.lang.UnsupportedOperationException
at java.util.AbstractList.add(AbstractList.java:148)
at java.util.AbstractList.add(AbstractList.java:108)
at ConvertArrayToArrayListExample.main(ConvertArrayToArrayListExample.java:51)