Java ArrayList.removeRange() – Syntax & Examples

Java ArrayList.removeRange() – Examples

In this tutorial, we will learn about the Java ArrayList.removeRange() method, and learn how to use this method to remove elements in a given index range, with the help of examples.

removeRange(fromIndex, toIndex)

ArrayList.removeRange() removes from this list all of the elements whose index is between fromIndex, inclusive, and toIndex, exclusive.

removeRange() is a protected method. So, to access this method, you may create a sub-class for the ArrayList and then access it via the object of sub-class, or you may need to create your class in the same package or sub packages of ArrayList. Accessing the method via sub-class is recommended.

Syntax

The syntax of removeRange() method with fromIndex and toIndex parameters is

removeRange(int fromIndex, int toIndex)

where

Parameter	Description
fromIndex	The index of first element to be removed from this ArrayList.
toIndex	The index after last element to be removed form this ArrayList.

Returns

The method returns void.

Example 1 – removeRange(fromIndex, toIndex)

In this example, we will create a class named Example as subclass for ArrayList<String>. So, now objects of Example can access protected classes of ArrayList<String>, like removeRange(). We will add five elements to this example object, and remove the elements in the range starting from 1 until 4 using removeRange() method.

Java Program

import java.util.ArrayList;

public class Example extends ArrayList<String> {
  public static void main(String[] args) {
	  Example list = new Example();  
	  list.add("a");  
	  list.add("b");  
	  list.add("c"); 
	  list.add("d");
	  list.add("e");
	  System.out.println("Original list            : " + list);
	  
	  int fromIndex = 1;
	  int toIndex = 4;
	  list.removeRange(fromIndex, toIndex);
	  System.out.println("List after removeRange() : " + list);
  }
}

Output

Original list            : [a, b, c, d, e]
List after removeRange() : [a, e]

Example 2 – removeRange(fromIndex, toIndex) – fromIndex < 0

If fromIndex is less than 0, removeRange() throws java.lang.ArrayIndexOutOfBoundsException.

Java Program

import java.util.ArrayList;

public class Example extends ArrayList<String> {
  public static void main(String[] args) {
	  Example list = new Example();  
	  list.add("a");  
	  list.add("b");  
	  list.add("c"); 
	  list.add("d");
	  list.add("e");
	  System.out.println("Original list            : " + list);
	  
	  int fromIndex = -2;
	  int toIndex = 4;
	  list.removeRange(fromIndex, toIndex);
	  System.out.println("List after removeRange() : " + list);
  }
}

Output

Original list            : [a, b, c, d, e]
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException
	at java.base/java.lang.System.arraycopy(Native Method)
	at java.base/java.util.ArrayList.shiftTailOverGap(Unknown Source)
	at java.base/java.util.ArrayList.removeRange(Unknown Source)
	at Example.main(Example.java:16)

Example 3 – removeRange(fromIndex, toIndex) – fromIndex > toIndex

If fromIndex is greater than toIndex, removeRange() throws java.lang.IndexOutOfBoundsException.

Java Program

import java.util.ArrayList;

public class Example extends ArrayList<String> {
  public static void main(String[] args) {
	  Example list = new Example();  
	  list.add("a");  
	  list.add("b");  
	  list.add("c"); 
	  list.add("d");
	  list.add("e");
	  System.out.println("Original list            : " + list);
	  
	  int fromIndex = 4;
	  int toIndex = 1;
	  list.removeRange(fromIndex, toIndex);
	  System.out.println("List after removeRange() : " + list);
  }
}

Output

Original list            : [a, b, c, d, e]
Exception in thread "main" java.lang.IndexOutOfBoundsException: From Index: 4 > To Index: 1
	at java.base/java.util.ArrayList.removeRange(Unknown Source)
	at Example.main(Example.java:15)

Example 4 – removeRange(fromIndex, toIndex) – toIndex > Length of List

If toIndex is greater than the length of the list, removeRange() throws java.lang.ArrayIndexOutOfBoundsException.

Java Program

import java.util.ArrayList;

public class Example extends ArrayList<String> {
  public static void main(String[] args) {
	  Example list = new Example();  
	  list.add("a");  
	  list.add("b");  
	  list.add("c"); 
	  list.add("d");
	  list.add("e");
	  System.out.println("Original list            : " + list);
	  
	  int fromIndex = 1;
	  int toIndex = 9;
	  list.removeRange(fromIndex, toIndex);
	  System.out.println("List after removeRange() : " + list);
  }
}

Output

Original list            : [a, b, c, d, e]
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException
	at java.base/java.lang.System.arraycopy(Native Method)
	at java.base/java.util.ArrayList.shiftTailOverGap(Unknown Source)
	at java.base/java.util.ArrayList.removeRange(Unknown Source)
	at Example.main(Example.java:15)

Conclusion

In this Java Tutorial, we have learnt the syntax of Java ArrayList.removeRange() method, and also learnt how to use this method with the help of examples.