What does the method trimToSize() do in java?

The trimToSize() method of the java.util.ArrayList class trims the capacity of this ArrayList instance to be the list's current size. An application can use this operation to minimize the storage of an ArrayList instance.

Example

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String args[]) {
      ArrayList<Integer> arrlist = new ArrayList<Integer>(5);
      arrlist.add(35);
      arrlist.add(20);
      arrlist.add(25);
      arrlist.trimToSize();
      for (Integer number : arrlist) {
         System.out.println("Number = " + number);
      }
   }
}

Output

Number = 35
Number = 20
Number = 25