In what scenarios does the ArrayIndexOutOfBoundsException exception in Java occur?

Java is a widely used programming language that provides many powerful features and libraries that can help developers quickly create complex applications. However, in Java programming, there are some errors and exceptions that can cause the program to crash, and ArrayIndexOutOfBoundsException is one of them.

ArrayIndexOutOfBoundsException is a runtime exception that is thrown when the program tries to access a non-existent location in the array. This exception indicates that the array has gone out of bounds or that an attempt was made to access an element that does not exist. Generally speaking, when a program throws an ArrayIndexOutOfBoundsException exception, it is usually caused by a coding error.

In Java, an array is an ordered collection of elements, each element can be accessed through a unique subscript. Array subscripts start from 0 and end with the array length minus 1. If an attempt is made to access an index outside this range, an ArrayIndexOutOfBoundsException will occur.

The following are some common scenarios that cause this exception:

1. The array subscript is out of range

When the program tries to access an array that does not exist When indexing, an ArrayIndexOutOfBoundsException exception will be thrown. For example, if you try to access an array of length 10, but the index is 11, an exception will occur. For example:

int[] numbers = new int[10];
int x = numbers[11]; // 抛出异常，下标超出范围

2. Use negative subscripts

Array subscripts can only be non-negative integers. If you try to access an array using a negative index, an ArrayIndexOutOfBoundsException is thrown. For example:

int[] numbers = new int[10];
int x = numbers[-1]; // 抛出异常，下标为负数

3. Initialization problem

If an error occurs when initializing an array, it may cause an ArrayIndexOutOfBoundsException exception when subsequently accessing the array. For example:

int[] numbers = new int[-1]; // 抛出异常，数组长度为负数

4. Multidimensional array

When using multidimensional arrays, ArrayIndexOutOfBoundsException exceptions may also occur. In this case, the exception is usually caused by accidentally accessing a non-existing array element. For example:

int[][] numbers = new int[2][2];
int x = numbers[2][1]; // 抛出异常，第一个下标超出范围

When the program throws an ArrayIndexOutOfBoundsException exception, we need to check the code first to ensure that non-existent elements are not accessed or exceed the length range of the array, and then debug. In order to avoid the occurrence of this exception, we recommend that before accessing the array elements, always check the length of the array and ensure that the element subscript does not exceed the bounds.

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