Java ArrayList subList() Method

June 7, 2023

What is ArrayList in java ?

Arraylist is a part of collection framework in java. It contains several inbuilt function like subList() method which can be found in the java.util.ArrayList Package. It implements the List interface of the collections framework.

Java ArrayList subList() Method :

Gives a view of the part of the list between the fromIndex and toIndex values that are specified. (The returned list is empty if the fromIndex and toIndex values are equal.)

Since this list supports the returned list, any non-structural changes made to the returned list will also be reflected in the other way around. The returned list supports all of the optional list operations.

Syntax :

public List subList(int fromIndex, int toIndex)

Parameters :

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

Throws Exception : IndexOutOfBoundsException - if an endpoint index value is out of range (fromIndex < 0 || toIndex > size) IllegalArgumentException - if the endpoint indices are out of order (fromIndex > toIndex)

Return value:

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

Polymorphism in Java

Encapsulation in Java

Abstraction in Java

Multithreading in Java

Example 1 :

Run

import java.util.ArrayList;
public class Main{
    public static void main(String[] args) {

        ArrayList list = new ArrayList<>();
        
        //Adding elements to the list
        list.add("A");      
        list.add("B");
        list.add("C");
        list.add("D");
        list.add("E");
        list.add("F");

        //Printing the subList from index 2 to 5
        System.out.println(list.subList(2, 5));
    }
}

Output :

[C, D, E]

Explanation : Here we have passed index 2 and 5 in the subList() method , and we get the output as [C, D, E] ,because the sublist() method do not include last index .It only print from start index to one less index which is passed in the subList() method.

Example 2 :

Run

import java.util.ArrayList;
public class Main{
    public static void main(String[] args) {

        ArrayList list = new ArrayList<>();
        
        //Adding elements to the list
        list.add("A");      
        list.add("B");
        list.add("C");
        list.add("D");
        list.add("E");
        list.add("F");

        //Printing the subList from index 2 to 7
        System.out.println(list.subList(2, 7));
    }
}

Output :

Exception in thread "main" java.lang.IndexOutOfBoundsException: toIndex = 7
        at java.base/java.util.AbstractList.subListRangeCheck(AbstractList.java:509)
        at java.base/java.util.ArrayList.subList(ArrayList.java:1108)
        at ArrayListSubList.main(ArrayListSubList.java:16)

Explanation : Since the array only has indexes up to 5, we are attempting to get the subList till index 7 from index 2 .As a result, following code execution, the compiler throws an exception for array index out of bond.

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Java ArrayList subList() Method

What is ArrayList in java ?

Java ArrayList subList() Method :

Syntax :

Parameters :

Return value:

Example 1 :

Output :

Example 2 :

Output :

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