List clear() method in Java with Examples

The clear() method of List interface in Java is used to remove all of the elements from the List container. This method does not deleted the List container, instead it just removes all of the elements from the List. 

Syntax:

public void clear()

Parameter: This method accepts does not accepts any parameter.

Return Value: The return type of the function is void and it does not returns anything. 

Exceptions: This method throws an UnsupportedOperationException if the clear() operation is not supported by this list. 

Below programs illustrate the List.clear() method: 

Program 1:

Java

// Java code to illustrate clear() method
import java.io.*;
import java.util.*;

public class ListDemo {
    public static void main(String[] args)
    {

        // create an empty list with an initial capacity
        List<String> list = new ArrayList<String>(5);

        // use add() method to initially
        // add elements in the list
        list.add("Geeks");
        list.add("For");
        list.add("Geeks");

        // Remove all elements from the List
        list.clear();

        // print the List
        System.out.println(list);
    }
}

Output:

[]

Program 2:

Java

// Java code to illustrate clear() method
import java.io.*;
import java.util.*;

public class ListDemo {
    public static void main(String[] args)
    {

        // create an empty list with an initial capacity
        List<Integer> list = new ArrayList<Integer>(5);

        // use add() method to initially
        // add elements in the list
        list.add(10);
        list.add(20);
        list.add(30);

        // clear the list
        list.clear();

        // prints all the elements available in list
        System.out.println(list);
    }
}

Output:

[]

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/List.html#clear()