5063455: (fmt) MissingFormatArgumentException.getFormatSpecifier() incorrect return value

Summary: updated the incorrect StringBuilder constructor usage
Reviewed-by: dholmes, sherman
Contributed-by: brandon.passanisi@oracle.com

src/share/classes/java/util/Formatter.java

@@ -2879,7 +2879,7 @@ public final class Formatter implements Closeable, Flushable {
         }
 
         public String toString() {
-            StringBuilder sb = new StringBuilder('%');
+            StringBuilder sb = new StringBuilder("%");
             // Flags.UPPERCASE is set internally for legal conversions.
             Flags dupf = f.dup().remove(Flags.UPPERCASE);
             sb.append(dupf.toString());

test/java/util/MissingFormatArgumentException/GetFormatSpecifier.java

+/*
+ * Copyright (c) 2011, 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.
+ */
+
+/*
+ * @test
+ * @bug     5063455
+ * @summary Unit test for MissingFormatArgumentException.getFormatSpecifier
+ * @author  Brandon Passanisi
+ */
+import java.util.MissingFormatArgumentException;
+
+public class GetFormatSpecifier {
+
+    static void fail(String s) {
+        throw new RuntimeException(s);
+    }
+
+    public static void main(String[] args) {
+
+        // Use the format specifier below, which should throw a
+        // MissingFormatArgumentException. Then, use getFormatSpecifier()
+        // to make sure the returned value equals the original format string.
+        final String formatSpecifier = "%1$5.3s";
+        try {
+            String formatResult = String.format(formatSpecifier);
+            fail("MissingFormatArgumentException not thrown.");
+        } catch (MissingFormatArgumentException ex) {
+            final String returnedFormatSpecifier = ex.getFormatSpecifier();
+            if (!returnedFormatSpecifier.equals(formatSpecifier)) {
+                fail("The specified format specifier: " + formatSpecifier
+                        + " does not match the value from getFormatSpecifier(): "
+                        + returnedFormatSpecifier);
+            }
+        }
+    }
+}