Java Exceptions — Free Java Tutorial

TL;DR: Learn Java Exceptions in Java with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Java Exceptions in Java

An exception is an unexpected event that disrupts normal program flow: dividing by zero, accessing a null reference, reading a file that doesn't exist. Java has a robust exception handling system using try-catch-finally blocks.

try: code that might throw an exception. catch: what to do when a specific exception occurs. finally: code that ALWAYS runs (use for cleanup — closing files, connections). throw: manually throw an exception. throws: declare that a method might throw an exception.

Checked exceptions (must be handled — IOException, SQLException) vs Unchecked exceptions (extend RuntimeException — NullPointerException, ArrayIndexOutOfBoundsException, NumberFormatException). Understanding the difference is important for Java exams.

try {
    // risky code
} catch (ExceptionType e) {
    // handle error
    System.out.println(e.getMessage());
} finally {
    // always executes
}

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