src/share/classes/java/util/JapaneseImperialCalendar.java

*** 944,1002 ****
          }
  
          set(field, getRolledValue(internalGet(field), amount, min, max));
      }
  
      public String getDisplayName(int field, int style, Locale locale) {
!         if (!checkDisplayNameParams(field, style, SHORT, LONG, locale,
                                      ERA_MASK|YEAR_MASK|MONTH_MASK|DAY_OF_WEEK_MASK|AM_PM_MASK)) {
              return null;
          }
  
          int fieldValue = get(field);
  
          // "GanNen" is supported only in the LONG style.
          if (field == YEAR
!             && (getBaseStyle(style) == SHORT || fieldValue != 1 || get(ERA) == 0)) {
              return null;
          }
  
!         String name = CalendarDataUtility.retrieveFieldValueName("japanese", field, fieldValue, style, locale);
          // If the ERA value is null, then
          // try to get its name or abbreviation from the Era instance.
          if (name == null && field == ERA && fieldValue < eras.length) {
              Era era = eras[fieldValue];
              name = (style == SHORT) ? era.getAbbreviation() : era.getName();
          }
          return name;
      }
  
      public Map<String,Integer> getDisplayNames(int field, int style, Locale locale) {
!         if (!checkDisplayNameParams(field, style, ALL_STYLES, LONG, locale,
                                      ERA_MASK|YEAR_MASK|MONTH_MASK|DAY_OF_WEEK_MASK|AM_PM_MASK)) {
              return null;
          }
!         Map<String, Integer> names = CalendarDataUtility.retrieveFieldValueNames("japanese", field, style, locale);
          // If strings[] has fewer than eras[], get more names from eras[].
          if (field == ERA) {
              int size = names.size();
              if (style == ALL_STYLES) {
!                 size /= 2; // SHORT and LONG
              }
              if (size < eras.length) {
                  int baseStyle = getBaseStyle(style);
                  for (int i = size; i < eras.length; i++) {
                      Era era = eras[i];
!                     if (baseStyle == ALL_STYLES || baseStyle == SHORT) {
                          names.put(era.getAbbreviation(), i);
                      }
                      if (baseStyle == ALL_STYLES || baseStyle == LONG) {
                          names.put(era.getName(), i);
                      }
                  }
              }
          }
          return names;
      }
  
      /**
       * Returns the minimum value for the given calendar field of this
--- 944,1014 ----
          }
  
          set(field, getRolledValue(internalGet(field), amount, min, max));
      }
  
+     @Override
      public String getDisplayName(int field, int style, Locale locale) {
!         if (!checkDisplayNameParams(field, style, SHORT, NARROW_FORMAT, locale,
                                      ERA_MASK|YEAR_MASK|MONTH_MASK|DAY_OF_WEEK_MASK|AM_PM_MASK)) {
              return null;
          }
  
          int fieldValue = get(field);
  
          // "GanNen" is supported only in the LONG style.
          if (field == YEAR
!             && (getBaseStyle(style) != LONG || fieldValue != 1 || get(ERA) == 0)) {
              return null;
          }
  
!         String name = CalendarDataUtility.retrieveFieldValueName(getCalendarType(), field,
!                                                                  fieldValue, style, locale);
          // If the ERA value is null, then
          // try to get its name or abbreviation from the Era instance.
          if (name == null && field == ERA && fieldValue < eras.length) {
              Era era = eras[fieldValue];
              name = (style == SHORT) ? era.getAbbreviation() : era.getName();
          }
          return name;
      }
  
+     @Override
      public Map<String,Integer> getDisplayNames(int field, int style, Locale locale) {
!         if (!checkDisplayNameParams(field, style, ALL_STYLES, NARROW_FORMAT, locale,
                                      ERA_MASK|YEAR_MASK|MONTH_MASK|DAY_OF_WEEK_MASK|AM_PM_MASK)) {
              return null;
          }
!         Map<String, Integer> names;
!         names = CalendarDataUtility.retrieveFieldValueNames(getCalendarType(), field, style, locale);
          // If strings[] has fewer than eras[], get more names from eras[].
+         if (names != null) {
              if (field == ERA) {
                  int size = names.size();
                  if (style == ALL_STYLES) {
!                     Set<Integer> values = new HashSet<>();
!                     // count unique era values
!                     for (String key : names.keySet()) {
!                         values.add(names.get(key));
!                     }
!                     size = values.size();
                  }
                  if (size < eras.length) {
                      int baseStyle = getBaseStyle(style);
                      for (int i = size; i < eras.length; i++) {
                          Era era = eras[i];
!                         if (baseStyle == ALL_STYLES || baseStyle == SHORT
!                                 || baseStyle == NARROW_FORMAT) {
                              names.put(era.getAbbreviation(), i);
                          }
                          if (baseStyle == ALL_STYLES || baseStyle == LONG) {
                              names.put(era.getName(), i);
                          }
                      }
                  }
              }
+         }
          return names;
      }
  
      /**
       * Returns the minimum value for the given calendar field of this