Exception Best Practices

The assert keyword checks internal invariants during development and is disabled by default in production, so it must never be used for public API validation where IllegalArgumentException should be used instead.

Always catch the most specific exception because broad catch hides bugs, never catch Throwable because it swallows JVM errors, and never use exceptions for control flow because they are expensive.

Throw early means validate and fail fast at the service entry point, while catch late means handle exceptions at the boundary layer that has enough context to decide the appropriate response.

throw e rethrows the same exception unchanged, throw new ServiceException(msg, e) wraps it in a domain exception with cause preserved, and Java 7 precise rethrow lets the compiler narrow catch(Exception e) to the actual types thrown.