Structured Logging (ARCH4158)

Key java.logging.structured-logging · Severity warning · Category logging

Building log messages with string concatenation hurts log aggregation and forces the string to be constructed even when the level is disabled. Use parameterized {} templates instead.

Incorrect

log.info("User " + userId + " created order " + orderId);

Correct

log.info("User {} created order {}", userId, orderId);

Fix

Write parameterized message templates using SLF4J’s {} placeholders instead of string concatenation.