The hardcoded '.' and '\\' parts have been modified to

EXTENSION_SEPARATOR
WINDOWS_FOLDER_SEPARATOR_CHAR.

The '\\' part can be added to WINDOWS_FOLDER_SEPARATOR_CHAR to maintain overall consistency in the codebase.

Author: J-unStiN

spring-core/src/main/java/org/springframework/util/StringUtils.java

@@ -60,6 +60,7 @@
  * @author Sam Brannen
  * @author Brian Clozel
  * @author Sebastien Deleuze
+ * @author SungJun Park
  * @since 16 April 2001
  */
 public abstract class StringUtils {
@@ -72,6 +73,8 @@ public abstract class StringUtils {
 
 	private static final String WINDOWS_FOLDER_SEPARATOR = "\\";
 
+	private static final char WINDOWS_FOLDER_SEPARATOR_CHAR = '\\';
+
 	private static final String DOUBLE_BACKSLASHES = "\\\\";
 
 	private static final String TOP_PATH = "..";
@@ -712,7 +715,7 @@ public static String cleanPath(String path) {
 
 		String normalizedPath;
 		// Optimize when there is no backslash
-		if (path.indexOf('\\') != -1) {
+		if (path.indexOf(WINDOWS_FOLDER_SEPARATOR_CHAR) != -1) {
 			normalizedPath = replace(path, DOUBLE_BACKSLASHES, FOLDER_SEPARATOR);
 			normalizedPath = replace(normalizedPath, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);
 		}
@@ -722,7 +725,7 @@ public static String cleanPath(String path) {
 		String pathToUse = normalizedPath;
 
 		// Shortcut if there is no work to do
-		if (pathToUse.indexOf('.') == -1) {
+		if (pathToUse.indexOf(EXTENSION_SEPARATOR) == -1) {
 			return pathToUse;
 		}