ZonedDateTime not serialised as UTC by default altough ObjectMapper Javadocs claiming UTC is the default #303

/**
 * Method for overriding default TimeZone to use for formatting.
 * Default value used is UTC (NOT default TimeZone of JVM).
 */

public ObjectMapper setTimeZone(TimeZone tz) {
    _deserializationConfig = _deserializationConfig.with(tz);
    _serializationConfig = _serializationConfig.with(tz);
    return this;
}

/**
 * Base settings contain defaults used for all {@link ObjectMapper}
 * instances.
 */
protected final static BaseSettings DEFAULT_BASE = new BaseSettings(
        null, // cannot share global ClassIntrospector any more (2.5+)
        DEFAULT_ANNOTATION_INTROSPECTOR,
         null, TypeFactory.defaultInstance(),
        null, StdDateFormat.instance, null,
        Locale.getDefault(),
        null, // to indicate "use Jackson default TimeZone" (UTC since Jackson 2.7)
        Base64Variants.getDefaultVariant(),
        // Only for 2.x; 3.x will use more restrictive default
        LaissezFaireSubTypeValidator.instance,
        // Since 2.12:
        new DefaultAccessorNamingStrategy.Provider(),
        // Since 2.16: [databind#2502] Add a way to configure Caches Jackson uses
        DefaultCacheProvider.defaultInstance()
);

    ObjectMapper testmapper = new ObjectMapper();
    testmapper.registerModule(new JavaTimeModule());
    testmapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
    ZonedDateTime testtime = ZonedDateTime.now(ZoneId.of("Europe/Berlin"));
    String teststring = testmapper.writeValueAsString(testtime);
    // 2024-02-20T11:37:42.009045+01:00

    testmapper = new ObjectMapper();
    testmapper.registerModule(new JavaTimeModule());
    testmapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
    testmapper.setTimeZone(TimeZone.getTimeZone("UTC"));
    testtime = ZonedDateTime.now(ZoneId.of("Europe/Berlin"));
    teststring = testmapper.writeValueAsString(testtime);
    // 2024-02-20T10:38:13.0324177Z