Print Instead Of Logger (ARCH4157)

Key java.logging.system-out-instead-of-logger · Severity warning · Category logging

Printing with System.out or System.err provides no log level, formatting, or destination routing. Such output cannot be collected, filtered, or correlated in production and hurts performance.

Incorrect

public void process(Order order) {
    System.out.println("Processing: " + order.id());
}

Correct

private static final Logger log = LoggerFactory.getLogger(OrderService.class);

public void process(Order order) {
    log.info("Processing: {}", order.id());
}

Fix

Use a logger such as SLF4J instead of System.out/System.err and choose an appropriate log level.