List add(E ele) method in Java with Examples

The add(E ele) method of List interface in Java is used to insert the specified element to the end of the current list.

Syntax:

public boolean add(E ele)

Parameter: This method accepts a single parameter ele which represents the element to be inserted at the end of this list.

Return Value: The function returns a boolean value True if the element is successfully inserted in the List otherwise it returns False.

Exceptions:

• UnsupportedOperationException – It throws this exception if the add() operation is not supported by this list.
• ClassCastException – It throws this exception if the class of the specified element prevents it from being added to this list.
• NullPointerException – It throws this exception if the specified element is null and this list does not permit null elements.
• IllegalArgumentException – It throws this exception if some property of this element prevents it from being added to this list.

Below programs illustrate the RoleList.add(Object obj) method:

Program 1:

// Java code to illustrate add(Object o)
import java.io.*;
import java.util.*;

public class ArrayListDemo {
    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 add elements in the list
        list.add(15);
        list.add(20);
        list.add(25);

        // prints all the elements available in list
        for (Integer number : list) {
            System.out.println("Number = " + number);
        }
    }
}

Output:

Number = 15
Number = 20
Number = 25

Program 2:

// Java code to illustrate add(Object o)
import java.io.*;
import java.util.*;

public class ArrayListDemo {
    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 add elements in the list
        list.add("Geeks");
        list.add("For");
        list.add("Geeks");

        // prints all the elements available in list
        for (String str : list) {
            System.out.print(str + " ");
        }
    }
}

Output:

Geeks For Geeks

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