ArrayList subList() method in Java with Examples

The subList() method of java.util.ArrayList class is used to return a view of the portion of this list between the specified fromIndex, inclusive, and toIndex, exclusive. (If fromIndex and toIndex are equal, the returned list is empty.)

The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa. The returned list supports all of the optional list operations.

Syntax:

public List subList(int fromIndex, int toIndex)

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

• fromIndex – low endpoint (inclusive) of the subList
• toIndex – high endpoint (exclusive) of the subList

Returns Value: This method returns a view of the specified range within this list.

Exception: This method throws the following Exception.

• IndexOutOfBoundsException – if an endpoint index value is out of range (fromIndex size)
• IllegalArgumentException – if the endpoint indices are out of order (fromIndex > toIndex)

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

Example 1:

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

import java.util.*;

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

        try {

            // Creating object of ArrayList<Integer>
            ArrayList<String>
                arrlist = new ArrayList<String>();

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

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

            // getting the subList
            // using subList() method
            List<String> arrlist2 = arrlist.subList(2, 4);

            // print the subList
            System.out.println("Sublist of arrlist: "
                               + arrlist2);
        }

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

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

Output:

Original arrlist: [A, B, C, D, E]
Sublist of arrlist: [C, D]

Example 2: For IndexOutOfBoundsException

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

import java.util.*;

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

            // Creating object of ArrayList<Integer>
            ArrayList<String>
                arrlist = new ArrayList<String>();

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

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

            // getting the subList
            // using subList() method
            System.out.println("\nEnd index value is out of range");
            List<String> arrlist2 = arrlist.subList(2, 7);

            // print the subList
            System.out.println("Sublist of arrlist: "
                               + arrlist2);
        }

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

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

Output:

Original arrlist: [A, B, C, D, E]

End index value is out of range
Exception thrown : java.lang.IndexOutOfBoundsException: toIndex = 7

Example 3: For IllegalArgumentException

// Java program to demonstrate
// subList() method
// for IllegalArgumentException

import java.util.*;

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

            // Creating object of ArrayList<Integer>
            ArrayList<String>
                arrlist = new ArrayList<String>();

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

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

            // getting the subList
            // using subList() method
            System.out.println("\nEndpoint indices "
                               + "are out of order"
                               + " (fromIndex > toIndex)");
            List<String> arrlist2 = arrlist.subList(7, 2);

            // print the subList
            System.out.println("Sublist of arrlist: "
                               + arrlist2);
        }

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

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

Output:

Original arrlist: [A, B, C, D, E]

Endpoint indices are out of order (fromIndex > toIndex)
Exception thrown: java.lang.IllegalArgumentException: fromIndex(7) > toIndex(2)