Index Out Of Bounds

What is an Index Out of Bounds Error?

An "Index Out of Bounds" (IOB) exception occurs in Java when you attempt to access or modify an element in an array using an index that falls outside the valid range of indices for that array. In Java, arrays are zero-indexed, which means the first element has an index of 0, the second element has an index of 1, and so on.

When you try to access an element with an index less than 0 or greater than or equal to the array's length, the "Index Out of Bounds" exception is thrown. This exception serves as a way for the Java program to indicate that you are attempting an invalid operation on the array.

Note
In Java, there are numerous exceptions. We will explore the exception hierarchy, learn how to create custom exceptions, and handle them correctly in a separate course.

There is an example that will throw an Index Out of Bounds exception:

Main


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package com.example;

public class Main {
    public static void main(String[] args) {
        int[] array = {1, 2, 3, 4, 5};
        int element = array[5]; // this line will cause an "Index out of bounds exception"
    }
}

To address the "Index Out of Bounds" exception, you can follow these steps:

Ensure that the index you use to access the array falls within the valid range of indices;
Verify that the array is not empty before attempting to access any elements;
Review your program's logic to confirm the accuracy of index calculations;
Use conditional statements or loops to prevent accessing elements beyond the valid index range.

Here's an example that demonstrates how to handle the Index Out of Bounds exception:

Main


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package com.example;

public class Main {
    public static void main(String[] args) {
        int[] array = {1, 2, 3};

        int index = 3; // Invalid index

        if (index >= 0 && index < array.length) {
            int element = array[index];
            System.out.println("Element at index " + index + ": " + element);
        } else {
            System.out.println("Invalid index");
        }
    }
}

In this example, we validate whether the index falls within the valid range before attempting to access the array. If the index is valid, we retrieve the element at that position. Otherwise, we manage the exception by displaying an error message.

1. When the ``Index Out of Bounds`` exception occurs?

2. How to solve ``IOB``?(select multiple answer choices)

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Section 4. Chapter 3

Java Basics

Index Out Of Bounds

What is an Index Out of Bounds Error?