Java Tutorial: Error Handling
try/catch/finally, checked vs unchecked exceptions, custom exception classes, multi-catch, and best practices.
When things go wrong
Exceptions are Java's way of saying "something unexpected happened — here's exactly what and where." A `NullPointerException` tells you more than a silent crash.
Understanding the difference between checked and unchecked exceptions is critical — it determines whether you MUST handle an error or CAN choose to handle it.
What you'll learn in this Java error handling tutorial
This interactive Java tutorial has 6 hands-on exercises. Estimated time: 18 minutes.
- try / catch / finally — When code might fail, wrap it in `try`. Catch specific exceptions in `catch`. `finally` runs ALWAYS — whether an excepti…
- Checked vs unchecked exceptions — **Checked exceptions** (e.g. `IOException`, `SQLException`) — must be caught or declared with `throws`.
- Multi-catch — Catch multiple exception types in one catch block with `|`:
- Custom exception classes — Create your own exception classes for domain-specific errors:
- try-with-resources — Resources like file handles and database connections MUST be closed — even if an exception occurs.
- Build a robust input parser — Final challenge — no starter code.
Java Error Handling concepts covered
- When things go wrong