UndefinedBehaviorError: java.lang.ArrayIndexOutOfBoundsException: 0

[faveoled]

import java.time.LocalDateTime
import java.time.format.DateTimeFormatterBuilder
import java.time.temporal.ChronoField
import java.time.format.TextStyle
import java.util.Locale
import java.time.format.DateTimeFormatter
import java.time.LocalDate
import java.time.ZoneId

val formatterFull: DateTimeFormatter = new DateTimeFormatterBuilder()
    .appendPattern("dd ")
    .appendText(ChronoField.MONTH_OF_YEAR, TextStyle.FULL_STANDALONE)
    .toFormatter(Locale.forLanguageTag("uk"))
val today = LocalDate.now(ZoneId.of("UTC"))
val todayString = today.format(formatterFull)
print(todayString)

This code works on JVM but fails with UndefinedBehaviorError on Scala.js

[cquiroz]

I wonder if any of those variables is null, that would produce UndefinedBehavior I think