ZGC sometimes prints doubles with an incorrect format string, "%lf" instead of "%f". The "l" doesn't cause any problems, but it also has no meaning when printing doubles, so it should be removed. Bug: https://bugs.openjdk.java.net/browse/JDK-8229129 Webrev: http://cr.openjdk.java.net/~pliden/8229129/webrev.0 /Per