AbstractList add(int index, E element) method in Java with Examples

The add(int index, E element) method of AbstractList is used to insert an element at the specified position in this list. The new element is inserted at the specified index in this list.

Syntax:

public void add(int index, E element)

Parameters: This method takes 2 parameters :-

1. index: index at which the specified element is to be inserted
2. element: element to be inserted

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

Exceptions:The exceptions present are :-

• ClassCastException: if the class of an element of this set is incompatible with the specified collection
• NullPointerException: if this set contains a null element and the specified collection does not permit null elements, or if the specified collection is null.
• UnsupportedOperationException: if the add operation is not supported by this list.
• IllegalArgumentException: if some property of the specified element prevents it from being added to this list.
• IndexOutOfBoundsException: if the index is out of range (index size()).

Below program illustrates the add(int index, int position) function of AbstractList class :

Program 1:

// Java code to illustrate AbstractList
// add(int index, int position) method

import java.io.*;
import java.util.*;

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

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

        // Use add() method
        // to add elements in the list
        list.add(3);
        list.add(6);
        list.add(9);
        list.add(12);

        // Prints all the elements
        // available in list
        System.out.println("Before: "
                           + list);

        // Add(int index, int element) method
        list.add(1, 4);

        // Prints all the elements
        // after the above method
        System.out.println("After: "
                           + list);
    }
}

Output:

Before: [3, 6, 9, 12]
After: [3, 4, 6, 9, 12]

Program 2:

// Java code to illustrate AbstractList
// add(int index, int position) method

import java.io.*;
import java.util.*;

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

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

        // Use add() method
        // to add elements in the list
        list.add("Geeks");
        list.add("for");
        list.add("Computer");
        list.add("Portal");

        // Prints all the elements
        // available in the list
        System.out.println("Before: " + list);

        // Add(int index, int element) method
        list.add(2, "Geeks");

        // Prints all the elements
        // after the above method
        System.out.println("After: " + list);
    }
}

Output:

Before: [Geeks, for, Computer, Portal]
After: [Geeks, for, Geeks, Computer, Portal]

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/AbstractList.html#add(int, %20E)