Handling Exceptions in Code: When Things Don’t Go as Planned
In the real world, things go wrong. In programming? They go wrong fast. And when they do, you don’t want your entire program to crash and burn. That’s where exception handling comes in.
What Is an Exception?
An exception is an unexpected event that happens during the execution of a program — something the system wasn’t prepared for. Examples include:
Dividing by zero
Accessing a missing file
Invalid user input
Network errors
When an exception occurs, the program stops unless you manage it. This leads to:
Lost data
A broken user experience
Frustrated users and developers
What Does an Exception Look Like?
When an exception occurs, it typically includes:
A message describing what went wrong
The type of exception (e.g., )
A stack trace — a list of method calls the program went through before it crashed
This trace is extremely useful for debugging.
The try...catch Block
To prevent a crash, you can wrap risky code in a block. If something goes wrong, the block handles the exception.
If an exception is thrown inside the , the block will run — and the program continues without crashing.
The finally Block
The block runs no matter what — whether an exception was thrown or not. It’s useful for cleanup actions, like closing files or freeing resources.
Throwing Your Own Exceptions
Sometimes you need to create an error on purpose — for example, when you detect bad input.
Use the keyword:
This lets you enforce rules and ensure your program behaves as expected.
Global Exception Handling
Instead of repeating everywhere, you can create a global exception handler — a central place that handles all unhandled exceptions. This improves maintainability and provides consistent error messages across the app.
In frameworks or apps (like Android), you can register a global handler to log exceptions, show user-friendly messages, or report errors to monitoring tools.
Summary
Handling exceptions is about building resilient, user-friendly programs that don't crash at the first sign of trouble.
Key takeaways:
Exceptions are unexpected events that stop normal execution
Use to manage them
Use for cleanup
Use to enforce your own rules
Consider a global handler to catch and manage unexpected errors across your application
With exception handling in place, your programs can gracefully recover, guide users properly, and avoid unnecessary crashes.