FP java:S4449 reports issue for null parameter for Guava Iterables.getLast

[ahubold (Andreas Hubold)]

• SonarQube Community Build v25.10.0.114319
• Java Code
• Rule java:S4449 Nullness of parameters should be guaranteed

S4449 reports an issue for the the following Java code:

package org.example;
import com.google.common.collect.Iterables;

import java.util.List;

public class S4449GuavaIterablesGetLast {
  Object test(List<Object> list) {
    return Iterables.getLast(list, null);
  }
}

It does not like the null parameter passed as defaultValue to Iterables#getLast of Guava version 33.5.0-jre.

The signature of the called Guava method is using org.jspecify.annotations.Nullable

  @ParametricNullness
  public static <T extends @Nullable Object> T getLast(
      Iterable<? extends T> iterable, @ParametricNullness T defaultValue) {

Because T is declared as “extends @Nullable Object”, it should be possible to pass null as defaultValue.

I’ve attached the above source as minimal maven project.

test.zip (1.9 KB)

Cheers,
Andreas

[anton.haubner]

Hello Andreas!

Thank you very much for the report and especially for the well-prepared reproducer.
Indeed, I can confirm that an FP is being raised here - null should be a valid argument in this context.

I created a ticket to track the problem here: Link

Best regards,

Anton