diff --git a/spring-core/src/main/java/org/springframework/util/StringUtils.java b/spring-core/src/main/java/org/springframework/util/StringUtils.java
index 04403a3692b..761799f2daa 100644
--- a/spring-core/src/main/java/org/springframework/util/StringUtils.java
+++ b/spring-core/src/main/java/org/springframework/util/StringUtils.java
@@ -416,14 +416,14 @@ public abstract class StringUtils {
 		int pos = 0;  // our position in the old string
 		int patLen = oldPattern.length();
 		while (index >= 0) {
-			sb.append(inString.substring(pos, index));
+			sb.append(inString, pos, index);
 			sb.append(newPattern);
 			pos = index + patLen;
 			index = inString.indexOf(oldPattern, pos);
 		}
 
 		// append any characters to the right of a match
-		sb.append(inString.substring(pos));
+		sb.append(inString, pos, inString.length());
 		return sb.toString();
 	}