Java Exceptions Cheat Sheet: Causes, Solutions, and Best Practices

Java exceptions are essential for handling unexpected events that may occur during program execution. This cheat sheet provides a quick reference guide to common Java exceptions, their causes, resolutions, best practices, and key points to remember.

Introduction

Java exceptions are runtime events that occur during program execution when something goes wrong. They can be caused by a variety of issues, including invalid inputs, unexpected behavior, or external factors. Understanding and handling exceptions is crucial for writing reliable and robust Java applications.

Null Pointer Exception

Cause: Attempting to access methods or fields on a null reference.

Resolution: Always check for null references before accessing them.

String name = null;
if (name != null) {
    int length = name.length();
}

Arithmetic Exception

Cause: Division by zero or other mathematical operations that result in undefined results.

Resolution: Use conditional statements to prevent division by zero.

int divisor = 0;
if (divisor != 0) {
    int result = 10 / divisor;
}

Array Index Out of Bounds Exception

Cause: Attempting to access an array element with an index that is outside the valid range.