Checked or Unchecked Exceptions in Java: When Should I Use Which?

Deciding Between Checked and Unchecked Exceptions in Java

In the realm of exception handling, Java offers two distinct categories: checked and unchecked exceptions. When creating custom exceptions for your code, it's crucial to determine whether they should fall under either category.

Determining Checked Exceptions

Checked exceptions should be employed for specific scenarios. They signal predictable yet unpreventable errors that callers have the potential to handle effectively. For instance:

• You attempt to read a file, but it gets deleted before the operation commences.

By throwing a checked exception, you inform the caller about this anticipated failure, enabling them to take appropriate action.

Identifying Unchecked Exceptions

Unchecked exceptions cover all scenarios that don't meet the criteria for checked exceptions. This includes:

• Programming bugs (invalid arguments or buggy method implementation) that the application cannot resolve during execution.
• Errors that are genuinely unpredictable or unrecoverable (e.g., StackOverflowError).

Additional Considerations

• Re-evaluation at Every Level: As you traverse the call stack, re-assess the exception type. If it's appropriate for your callers to handle the error, throw a checked exception. Otherwise, wrap it in an unchecked exception.
• Abstraction Level: Use exceptions at the appropriate level of abstraction. Avoid exposing implementation-specific details (e.g., SQLException) and wrap them in more generic abstractions (e.g., RepositoryException).

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