Use fixed Locale for upcasing

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/io/trunk@1299947 13f79535-47bb-0310-9956-ffa450edef68

Author: sebbASF

src/main/java/org/apache/commons/io/input/XmlStreamReader.java

@@ -29,6 +29,7 @@
 import java.net.URL;
 import java.net.URLConnection;
 import java.text.MessageFormat;
+import java.util.Locale;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -628,7 +629,7 @@ static String getContentTypeMime(String httpContentType) {
      * httpContentType is NULL.
      *
      * @param httpContentType the HTTP content type
-     * @return The content type encoding
+     * @return The content type encoding (upcased)
      */
     static String getContentTypeEncoding(String httpContentType) {
         String encoding = null;
@@ -638,7 +639,7 @@ static String getContentTypeEncoding(String httpContentType) {
                 String postMime = httpContentType.substring(i + 1);
                 Matcher m = CHARSET_PATTERN.matcher(postMime);
                 encoding = (m.find()) ? m.group(1) : null;
-                encoding = (encoding != null) ? encoding.toUpperCase() : null;
+                encoding = (encoding != null) ? encoding.toUpperCase(Locale.US) : null;
             }
         }
         return encoding;