Code Quality
Dead Code in Java: How to Identify and Eliminate It
Dead code in Java includes unreachable statements after return/throw, unused private methods, and branches that can never be true. Some are compiler errors; others need tools.
❌ Unreachable and Dead Code
public class OrderProcessor {
public double processOrder(Order order) {
if (order == null) throw new IllegalArgumentException('null');
return calculateTotal(order);
System.out.println('Processing done'); // Unreachable!
}
private void sendLegacyEmail(Order o) { // Never called!
// Old implementation, replaced but not removed
}
}✅ Cleaned Up
public class OrderProcessor {
public double processOrder(Order order) {
if (order == null) throw new IllegalArgumentException('null');
return calculateTotal(order);
}
private double calculateTotal(Order order) {
return order.getItems().stream().mapToDouble(Item::getPrice).sum();
}
}💡
Pro tip: SonarQube's squid:S1172 and squid:S1854 rules find dead code that compilers miss. Run it in CI to prevent new dead code from entering the codebase.
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