ADDITIONAL SYSTEM INFORMATION :
Windows 10 / OpenJDK 11.0.1

A DESCRIPTION OF THE PROBLEM :
CLDRCalendarDataProviderImpl seems to have some bug that is logged on CONFIG level which maps to INFO level when one uses the SLF4J bridge for JUL.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Start a JShell and execute the snippet given below

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No log output about things that should not happen
ACTUAL -
Feb 12, 2019 5:20:54 PM sun.util.locale.provider.LocaleServiceProviderPool config
CONFIG: A locale sensitive service provider returned null for a localized objects, which should not happen. provider: sun.util.cldr.CLDRCalendarDataProviderImpl@887af79 locale: en
Feb 12, 2019 5:20:54 PM sun.util.locale.provider.LocaleServiceProviderPool config
CONFIG: A locale sensitive service provider returned null for a localized objects, which should not happen. provider: sun.util.cldr.CLDRCalendarDataProviderImpl@887af79 locale: en
Feb 12, 2019 5:20:54 PM sun.util.locale.provider.LocaleServiceProviderPool config
CONFIG: A locale sensitive service provider returned null for a localized objects, which should not happen. provider: sun.util.cldr.CLDRCalendarDataProviderImpl@887af79 locale: en
Feb 12, 2019 5:20:54 PM sun.util.locale.provider.LocaleServiceProviderPool config
CONFIG: A locale sensitive service provider returned null for a localized objects, which should not happen. provider: sun.util.cldr.CLDRCalendarDataProviderImpl@887af79 locale: en
$14 ==> java.text.SimpleDateFormat@5a0f0632

The four log lines are:
* once for current locale `"en"`, key `"firstDayOfWeek"`
* once for current locale `""`, key `"firstDayOfWeek"`
* once for current locale `"en"`, key `"minimalDaysInFirstWeek"`
* once for current locale `""`, key `"minimalDaysInFirstWeek"`
in sun.util.locale.provider.LocaleServiceProviderPool#getLocalizedObjectImpl

My guess is that maybe this commit causes the issue: http://hg.openjdk.java.net/jdk/jdk/rev/57148c79bd75

---------- BEGIN SOURCE ----------
import java.text.SimpleDateFormat;
import java.util.logging.ConsoleHandler;
import java.util.logging.Logger;

import static java.util.Arrays.stream;
import static java.util.Locale.ENGLISH;
import static java.util.logging.Level.ALL;
import static java.util.logging.LogManager.getLogManager;

    ConsoleHandler handler = new ConsoleHandler();
    handler.setLevel(ALL)

    Logger rootLogger = getLogManager().getLogger("");
    stream(rootLogger.getHandlers()).forEach(rootLogger::removeHandler)
    rootLogger.setLevel(ALL)
    rootLogger.addHandler(handler)

    new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z", ENGLISH)

---------- END SOURCE ----------

FREQUENCY : always