What are the commonly used exception handling tools in Java function libraries?

The Java function library provides a wealth of exception handling tools: 1. Built-in exception classes represent different error types. 2. Try-catch block handles exceptions. 3. The throws keyword declares exceptions that may be thrown by a method. 4. Customize exception classes to create domain-specific errors. Through try-catch blocks and custom exception classes, programmers can handle and recover from runtime errors to ensure application robustness.

Common exception handling tools in Java function libraries

Exception handling is a crucial concept in Java that allows Programmers handle and recover from run-time errors. The Java function library provides rich exception handling tools to simplify the error handling process.

1. Built-in exception classes

The Java language has a series of built-in exception classes that represent different types of errors, such as:

• NullPointerException: Thrown when trying to access a null reference.
• ArrayIndexOutOfBoundsException: Thrown when accessing the array exceeds the bounds.
• ArithmeticException: Thrown when performing an invalid arithmetic operation.

2. try-catch Block

try-catch The block is the basic block for handling exceptions. structure. It attempts to execute the code block and, if an exception occurs, executes the corresponding catch block:

try {
    // 代码可能引发异常
} catch (Exception e) {
    // 异常处理逻辑
}

3. throws Keywords

The throws keyword is used to declare exceptions that a method may throw. This allows the caller to be aware of exceptions that may be thrown by the method so they can handle them themselves.

4. Custom exception classes

In addition to the built-in exception classes, you can also create custom exception classes to represent specific errors. This helps distinguish domain-specific errors from other types of errors.

Practical case:

Consider the following code:

public void calculateAverage(int[] numbers) {
    int sum = 0;
    for (int number : numbers) {
        sum += number;
    }
    return sum / numbers.length;
}

If the numbers array is empty, this method will throw a ArithmeticException. To handle this exception, you can use a try-catch block:

public void calculateAverageSafely(int[] numbers) {
    try {
        int sum = 0;
        for (int number : numbers) {
            sum += number;
        }
        return sum / numbers.length;
    } catch (ArithmeticException e) {
        System.out.println("Cannot calculate average for an empty array");
    }
}

This code tries to calculate the average, catches the exception if the array is empty and prints an error message.

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