8273924: ArrayIndexOutOfBoundsException thrown in java.util.JapaneseImperialCalendar.add()

Backport-of: d39aad92308fbc28bd2de164e331062ebf62da85

Author: Yoshiki Sato

src/java.base/share/classes/sun/util/calendar/BaseCalendar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -277,6 +277,10 @@ void normalizeMonth(CalendarDate date) {
             long xm = 1L - month;
             year -= (int)((xm / 12) + 1);
             month = 13 - (xm % 12);
+            if (month == 13) {
+                year++;
+                month = 1;
+            }
             bdate.setNormalizedYear(year);
             bdate.setMonth((int) month);
         } else if (month > DECEMBER) {

test/jdk/java/util/Calendar/CalendarTestScripts/JapaneseTests.java

@@ -24,7 +24,7 @@
 /*
  * @test
  * @summary tests Japanese Calendar.
- * @bug 4609228 8187649
+ * @bug 4609228 8187649 8273924
  * @modules java.base/sun.util
  *          java.base/sun.util.calendar
  * @compile

test/jdk/java/util/Calendar/CalendarTestScripts/japanese/japanese_add.cts

@@ -354,6 +354,26 @@ test add MONTH
 #	check date Heisei $max Aug 16
 #	check timeofday 23 59 59 999
 
+#	JDK-8273924
+	set date Reiwa 2 Mar 1
+	add month -10
+	check date Reiwa 1 May 1
+	set date Reiwa 2 Mar 1
+	add month -11
+	check date Heisei 31 Apr 1
+	set date Reiwa 2 Mar 1
+	add month -12
+	check date Heisei 31 Mar 1
+	set date Reiwa 2 Mar 1
+	add month -13
+	check date Heisei 31 Feb 1
+	set date Reiwa 2 Mar 1
+	add month -14
+	check date Heisei 31 Jan 1
+	set date Reiwa 2 Mar 1
+	add month -15
+	check date Heisei 30 Dec 1
+
 test add WEEK_OF_YEAR
     use jcal
 	clear all