Java ArrayList subList() Method

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Description

The Java ArrayList subList() method returns a view of the portion of this list using the fromIndex(inclusive), and toIndex(exclusive). If fromIndex and toIndex are equal, it will return empty list. Any non-structural changes in the returned list are reflected in the original list as well, and vice-versa. The returned list supports list operations as well.

Declaration

Following is the declaration for java.util.ArrayList.subList() method

public List<E> subList(int fromIndex, int toIndex)

Parameters

fromIndex − The index of the start element (inclusive).

toIndex − The index of the end element (exclusive) .

Return Value

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

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).

Getting a SubList from an ArrayList of Integers Example

The following example shows the usage of Java ArrayList subList() method. We're creating a ArrayList of Integers. We're adding couple of Integers to the ArrayList object using add() method calls per element and using subList() method, we're getting a portion of the list and printing that portion in the end.

package com.tutorialspoint;

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String[] args) {
      
      // create an empty array list 
      ArrayList<Integer> arrayList = new ArrayList<>();

      // use add() method to add elements in the arrayList
      arrayList.add(0);
      arrayList.add(1);
      arrayList.add(2);
      arrayList.add(3);
      arrayList.add(4);
      arrayList.add(5);
      arrayList.add(6);
	  
      // get and print a sublist
      System.out.println(arrayList.subList(1,3));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

[1, 2]

Getting a SubList from an ArrayList of Strings Example

The following example shows the usage of Java ArrayList subList() method. We're creating a ArrayList of Strings. We're adding couple of Strings to the ArrayList object using add() method calls per element and using subList() method, we're getting a portion of the list and printing that portion in the end.

package com.tutorialspoint;

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String[] args) {
      
      // create an empty array list
      ArrayList<String> arrayList = new ArrayList<>();

      // use add() method to add elements in the arrayList
      arrayList.add("A");
      arrayList.add("B");
      arrayList.add("C");
      arrayList.add("D");
      arrayList.add("E");
      arrayList.add("F");
	  
      // get and print a sublist
      System.out.println(arrayList.subList(1,3));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

[B, C]

Getting a SubList from an ArrayList of Objects Example

The following example shows the usage of Java ArrayList subList() method. We're creating a ArrayList of Student objects. We're adding couple of Student objects to the ArrayList object using add() method calls per element and using subList() method, we're getting a portion of the list and printing that portion in the end.

package com.tutorialspoint;

import java.util.ArrayList;

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

      // create an empty arrayList
      ArrayList<Student> arrayList = new ArrayList<>();

      // use add() method to add elements in the arrayList
      arrayList.add(new Student(1, "Julie"));
      arrayList.add(new Student(2, "Robert"));
      arrayList.add(new Student(3, "Adam"));
	  
      // get and print a sublist
      System.out.println(arrayList.subList(1,3));   
   }
}

class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
   
   @Override
   public boolean equals(Object obj) {
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }
}

Output

Let us compile and run the above program, this will produce the following result −

[[ 2, Robert ], [ 3, Adam ]]