Java and Kotlin Exception Handling Best Practices

This article discusses exception handling in Java and Kotlin, detailing the hierarchy of checked and unchecked exceptions, providing examples such as ClassNotFoundException , IOException , NullPointerException , and Error subclasses. It explains that Kotlin treats all exceptions as unchecked, which creates challenges in mixed Java/Kotlin projects.

The authors propose aligning Kotlin with Java's checked exception concept using lint checks to enforce explicit declaration and handling of exceptions that require caller attention. Guidelines are defined for throwing exceptions: avoid top-level throws, throw specific checked exceptions, prefer custom exceptions like DAOException or ServiceException , and avoid throwing unchecked exceptions or Throwable directly.

For catching exceptions, the article emphasizes handling exceptions appropriately, not swallowing them, propagating when necessary, logging via a Monitor interface, distinguishing stable vs unstable code, avoiding overly broad try-catch blocks, and never using return in finally blocks.

The summary concludes that the defined strict rules, supported by lint checks in merge requests, aim to improve application quality by reducing crashes caused by improper exception usage.