Multicatch

Multicatch is a programming language feature that allows a single catch clause to handle multiple exception types. It is designed to reduce boilerplate when several different exceptions require the same recovery or logging behavior. By grouping related error types, multicatch can simplify error handling without sacrificing readability and maintainability.

The feature is most closely associated with Java, where a catch clause can specify multiple exception types separated by a vertical bar, for example: catch (IOException | SQLException ex) { … }. This means either IOException or SQLException will be handled by the same block. Other languages implement similar ideas under different names or with different syntax; for instance, Python can catch multiple exceptions in one block using a tuple, though it is not commonly described as multicatch. The exact rules and syntax vary by language, and not all languages offer a direct multicatch equivalent.

Syntax and semantics in languages that support multicatch generally involve listing the exception types in a single catch clause, with the catch parameter representing a common supertype of all listed exceptions. The catch variable is typically effectively final, meaning it cannot be reassigned within the block. Because a single block handles multiple exceptions, any handling code must be appropriate for all listed types, or the programmer may choose to inspect the actual exception type at runtime if necessary.

Benefits include reduced repetition and clearer intent when the same handling applies to different errors. Limitations include the loss of fine-grained, type-specific handling within the same block; if different exceptions require distinct responses, separate catch blocks may be clearer. Multicatch is most valuable when the recovery or logging logic is uniform across the involved exception types.

Example (Java-like syntax): try { … } catch (IOException | SQLException ex) { log(ex); }