This combination of a method name (minus) and parameter name (amountToAdd) looks suspicious:
* public JapaneseDate minus(long amountToAdd, TemporalUnit unit)
* public MinguoDate minus(long amountToAdd, TemporalUnit unit)
* public ThaiBuddhistDate minus(long amountToAdd, TemporalUnit unit)
* public JapaneseDate minus(long amountToAdd, TemporalUnit unit)
* public MinguoDate minus(long amountToAdd, TemporalUnit unit)
* public ThaiBuddhistDate minus(long amountToAdd, TemporalUnit unit)