src/share/classes/sun/text/resources/ja/FormatData_ja.java

*** 102,111 ****
--- 102,122 ----
                      "\u6728", // abb Thursday
                      "\u91d1", // abb Friday
                      "\u571f"  // abb Saturday
                  }
              },
+             { "DayNarrows",
+                 new String[] {
+                     "\u65e5",
+                     "\u6708",
+                     "\u706b",
+                     "\u6c34",
+                     "\u6728",
+                     "\u91d1",
+                     "\u571f",
+                 }
+             },
              { "AmPmMarkers",
                  new String[] {
                      "\u5348\u524d", // am marker
                      "\u5348\u5f8c" // pm marker
                  }