What does the method clear() do in java?

The clear() method of the class java.util.ArrayList removes all of the elements from this list. The list will be empty after this call returns.

Example

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String[] args) {
      ArrayList<Integer> arrlist = new ArrayList<Integer>(5);
      arrlist.add(20);
      arrlist.add(30);
      arrlist.add(10);
      arrlist.add(50);
      for (Integer number : arrlist) {
         System.out.println("Number = " + number);
      }
      int retval = arrlist.size();
      System.out.println("List consists of "+ retval +" elements");
      System.out.println("Performing clear operation !!");
      arrlist.clear();
      retval = arrlist.size();
      System.out.println("Now, list consists of "+ retval +" elements");
   }
}

Output

Number = 20
Number = 30
Number = 10
Number = 50
List consists of 4 elements
Performing clear operation !!
Now, list consists of 0 elements