AbstractList addAll() method in Java with Examples

The addAll() method of java.util.AbstractList class is used to insert all of the elements in the specified collection into this list at the specified position.

• This shifts the element currently at that position (if any) and any subsequent elements to the right (increases their indices).
• The new elements will appear in this list in the order that they are returned by the specified collection’s iterator.
• The behavior of this operation is undefined if the specified collection is modified while the operation is in progress.

This implementation gets an iterator over the specified collection and iterates over it, inserting the elements obtained from the iterator into this list at the appropriate position, one at a time, using add(int, E). Many implementations will override this method for efficiency.

Syntax:

public boolean addAll(int index, Collection c)

Parameters: This method takes the following argument as a parameter.

• index- the index at which to insert the first element from the specified collection
• c- the collection containing elements to be added to this list

• Return Value: This method returns true if this list changed as a result of the call.

• Exception: This method throws the following Exception.
  • NullPointerException – if the specified collection contains one or more null elements and this list does not permit null elements, or if the specified collection is null
  • IndexOutOfBoundsException – if the index is out of range (index size()).

Below are the examples to illustrate the addAll() method.

Example 1:

// Java program to demonstrate
// addAll() method
// for String value

import java.util.*;

public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {

        try {

            // Creating object of AbstractList<String>
            AbstractList<String>
                arrlist1 = new ArrayList<String>();

            // Populating arrlist1
            arrlist1.add("A");
            arrlist1.add("B");
            arrlist1.add("C");
            arrlist1.add("D");
            arrlist1.add("E");

            // print arrlist1
            System.out.println("Original ArrayListlist : "
                               + arrlist1);

            // Creating another object of AbstractList<String>
            AbstractList<String>
                arrlist2 = new ArrayList<String>();

            // Populating arrlist2
            arrlist2.add("X");
            arrlist2.add("Y");
            arrlist2.add("Z");

            // print arrlist2
            System.out.println("ArrayList elements "
                               + "to be added : "
                               + arrlist2);

            // adding the specified element
            // starting from index 2
            // using addAll() method
            boolean value = arrlist1.addAll(2, arrlist2);

            // print the value
            System.out.println("Operation successful : "
                               + value);

            // print the new arrlist
            System.out.println("New ArrayList : "
                               + arrlist1);
        }

        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }

        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

Original ArrayListlist : [A, B, C, D, E]
ArrayList elements to be added : [X, Y, Z]
Operation successful : true
New ArrayList : [A, B, X, Y, Z, C, D, E]

Example 2: For NullPointerException

// Java program to demonstrate
// addAll() method
// for NullPointerException

import java.util.*;

public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {

            // Creating object of AbstractList<String>
            AbstractList<String>
                arrlist1 = new ArrayList<String>();

            // Populating arrlist1
            arrlist1.add("A");
            arrlist1.add("B");
            arrlist1.add("C");
            arrlist1.add("D");
            arrlist1.add("E");

            // print arrlist1
            System.out.println("Original ArrayListlist : "
                               + arrlist1);

            // Creating another object of AbstractList<String>
            AbstractList<String> arrlist2 = null;

            // printing the arrlist2
            System.out.println("ArrayList to be added : "
                               + arrlist2);

            // adding the specified element
            // starting from index 2
            // using addAll() method
            System.out.println("\nTrying to get"
                               + " the null collection");
            boolean value = arrlist1.addAll(2, arrlist2);

            // print the value
            System.out.println("operation successful : "
                               + value);

            // print the new arrlist
            System.out.println("New ArrayList : "
                               + arrlist1);
        }

        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }

        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

Original ArrayListlist : [A, B, C, D, E]
ArrayList to be added : null

Trying to get the null collection
Exception thrown : java.lang.NullPointerException

Example 3: For IndexOutOfBoundsException

// Java program to demonstrate
// addAll() method
// for IndexOutOfBoundsException

import java.util.*;

public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {

        try {

            // Creating object of AbstractList<String>
            AbstractList<String>
                arrlist1 = new ArrayList<String>();

            // Populating arrlist1
            arrlist1.add("A");
            arrlist1.add("B");
            arrlist1.add("C");
            arrlist1.add("D");
            arrlist1.add("E");

            // print arrlist1
            System.out.println("Original ArrayListlist : "
                               + arrlist1);

            // Creating another object of AbstractList<String>
            AbstractList<String>
                arrlist2 = new ArrayList<String>();

            // Populating arrlist2
            arrlist2.add("X");
            arrlist2.add("Y");
            arrlist2.add("Z");

            // print arrlist2
            System.out.println("ArrayList elements to be added : "
                               + arrlist2);

            // adding the specified element
            // starting from index 2
            // using addAll() method
            System.out.println("\nTrying to put the out"
                               + " of range index ");
            boolean value = arrlist1.addAll(-1, arrlist2);

            // print the value
            System.out.println("operation succecfull : "
                               + value);

            // print the new arrlist
            System.out.println("New ArrayList : " + arrlist1);
        }

        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }

        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

Original ArrayListlist : [A, B, C, D, E]
ArrayList elements to be added : [X, Y, Z]

Trying to put the out of range index 
Exception thrown : java.lang.IndexOutOfBoundsException: Index: -1, Size: 5