Merge pull request stleary#1014 from Md-Yasir/enhancement/string-check

changed string checking logic

Author: stleary

src/main/java/org/json/CDL.java

@@ -183,7 +183,7 @@ public static String rowToString(JSONArray ja, char delimiter) {
             Object object = ja.opt(i);
             if (object != null) {
                 String string = object.toString();
-                if (string.length() > 0 && (string.indexOf(delimiter) >= 0 ||
+                if (!string.isEmpty() && (string.indexOf(delimiter) >= 0 ||
                         string.indexOf('\n') >= 0 || string.indexOf('\r') >= 0 ||
                         string.indexOf(0) >= 0 || string.charAt(0) == '"')) {
                     sb.append('"');