--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/util/Locale/bcp47u/spi/provider/foo/DateFormatSymbolsProviderImpl.java	Wed Aug 01 09:33:56 2018 -0700
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2018, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package foo;
+
+import java.text.DateFormatSymbols;
+import java.text.spi.DateFormatSymbolsProvider;
+import java.util.Locale;
+
+/*
+ * Implements DateFormatSymbolsProvider SPI, in order to check if the
+ * extensions work correctly.
+ */
+public class DateFormatSymbolsProviderImpl extends DateFormatSymbolsProvider {
+    private static final Locale AA = Locale.forLanguageTag("en-AA");
+    private static final Locale USJCAL = Locale.forLanguageTag("en-US-u-ca-japanese");
+    private static final Locale[] avail = {AA, Locale.US};
+
+    @Override
+    public Locale[] getAvailableLocales() {
+        return avail;
+    }
+
+    @Override
+    public boolean isSupportedLocale(Locale l) {
+        // Overriding to check the relation between
+        // isSupportedLocale/getAvailableLocales works correctly
+        if (l.equals(AA)) {
+            // delegates to super, as if isSupportedLocale didn't exist.
+            return super.isSupportedLocale(l);
+        } else {
+            return (l.equals(USJCAL));
+        }
+    }
+
+    @Override
+    public DateFormatSymbols getInstance(Locale l) {
+        return new MyDateFormatSymbols(l);
+    }
+
+    class MyDateFormatSymbols extends DateFormatSymbols {
+        Locale locale;
+
+        public MyDateFormatSymbols(Locale l) {
+            super(l);
+            locale = l;
+        }
+
+        @Override
+        public String[] getMonths() {
+            String[] ret = super.getMonths();
+            // replace the first item with some unique value
+            if (locale.stripExtensions().equals(AA)) {
+                ret[0] = "foo";
+            } else if (locale.equals(USJCAL)) {
+                ret[0] = "bar";
+            } else {
+                throw new RuntimeException("Unsupported locale: " + locale);
+            }
+            return ret;
+        }
+    }
+}