Mastering the Art of Removing Elements in Java ArrayList
When working with Java ArrayList, there are times when you need to remove a range of elements from the list. This is where the removeRange() method comes into play. But, did you know that this method is protected and can only be accessed within the class/package/subclass?
Understanding the Syntax
The removeRange() method takes two essential parameters: fromIndex and toIndex. These parameters define the range of elements to be removed from the ArrayList. fromIndex specifies the starting position, while toIndex marks the ending position. However, it’s crucial to note that the element at toIndex is not included in the removal process.
How it Works
When you call the removeRange() method, it doesn’t return any values. Instead, it modifies the ArrayList by removing the specified range of elements. This method throws an IndexOutOfBoundsException if fromIndex or toIndex is out of range or if toIndex is less than fromIndex.
A Closer Look at the Example
In our first example, we extend the ArrayList class to access the protected removeRange() method. This allows us to create an ArrayList using the Main class and remove a range of elements. However, this approach is not commonly used in Java.
A More Practical Approach
In our second example, we demonstrate a more practical way to remove multiple elements from an ArrayList. We create an ArrayList named numbers and use the subList() method to return elements at index 1 and 2. Then, we call the clear() method to remove these elements from the list.
Exploring Other Removal Methods
In addition to removeRange(), Java ArrayList offers other removal methods that can be useful in different scenarios. These include remove(), removeAll(), and removeIf(). Each method has its unique functionality, and understanding their differences can help you write more efficient code.