Java Program to Get Sublist of an ArrayList

Java Program to Get Sublist of an ArrayList

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In this article we will learn how to get a sublist from an ArrayList in Java.

Java Program to Get Sublist of an ArrayList

Sublist means a portion of a list.

In java, subList() is a builtIn method of java.util.ArrayList class that is used to extract a portion of an Arraylist from the specified index beginIndex(inclusive) to the specified index endIndex(exclusive).

Like subList(begin)

Parameters:

  1. beginIndex: It is the first parameter of the method. It is the start index of the sublist which is inclusive.
  2. endIndex: It is the second parameter of the method. It is the end Index of the sublist which is exclusive.

Syntax:

 public List subList( int beginIndex ,int endIndex)

Returns:  A view within the range specified in the parameters.

But while using subList() method, we have to keep look on two exceptions mainly.

Those are,

  1. IndexOutOfBoundsException: If the specified indexes are out of the range of ArrayList (beginIndex < 0 || endIndex > listsize).
  2. IllegalArgumentException: If the starting index is greater than the end point index (beginIndex > endIndex).

Now let’s see program to understand it more clearly.

Method: Java Program to Get Sublist of an ArrayList By Using subList() Method

Approach:

  1. Declare an ArrayList of String say arraylist
  2. Add elements into the Arraylist using add() method.
  3. Extract a subList from an ArrayList by using subList() Also, typecast the resulting sublist.
  4. Extract a sublist from List using subList() method without typecasting.

Program:

import java.util.ArrayList;
import java.util.List;

public class Main 
{
 public static void main(String args[])
 {
     //ArrayList declared
     ArrayList<String> arraylist = new ArrayList<String>();

     //Addition of elements in ArrayList
     arraylist.add("Java");
     arraylist.add("Scala");
     arraylist.add("Python");
     arraylist.add("Kotlin");
    
     //Display elements of original ArrayList
     System.out.println("Original ArrayList elements: "+ arraylist);

     //Extracting Sublist From ArrayList
     ArrayList<String> sl1 = new ArrayList<String>(arraylist.subList(1, 4));
     System.out.println("SubList stored in ArrayList: "+ sl1);

     //Extracting Sublist from List
     List<String> sl2 = arraylist.subList(1, 3);
     System.out.println("SubList stored in List: "+ sl2);
  }
}


Output:

Original ArrayList elements: [Java, Scala, Python, Kotlin]
SubList stored in ArrayList: [Scala, Python, Kotlin]
SubList stored in List: [Scala, Python]

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