JavaSE 6 西暦で与えられた日付文字列を和暦に変換する

package com.example.era;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class EraMain {

    public static void main(String[] args) {
        String todayStr = "2018/12/25";
        DateFormat seirekiFormat = new SimpleDateFormat("yyyy/MM/dd", Locale.JAPAN);
        Date today = null;
        try {
            today = seirekiFormat.parse(todayStr);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        DateFormat warekiFormat = new SimpleDateFormat("GGGGyyyy年MM月dd日", new Locale("ja", "JP", "JP"));
        System.out.println(warekiFormat.format(today));
    }

}