diff --git a/spring-core/src/main/java/org/springframework/util/backoff/FixedBackOff.java b/spring-core/src/main/java/org/springframework/util/backoff/FixedBackOff.java
index cf6514125e8..b4d80c48122 100644
--- a/spring-core/src/main/java/org/springframework/util/backoff/FixedBackOff.java
+++ b/spring-core/src/main/java/org/springframework/util/backoff/FixedBackOff.java
@@ -109,14 +109,12 @@ public class FixedBackOff implements BackOff {
 
 		@Override
 		public String toString() {
-			final StringBuilder sb = new StringBuilder("FixedBackOff{");
-			sb.append("interval=").append(FixedBackOff.this.interval);
 			String attemptValue = (FixedBackOff.this.maxAttempts == Long.MAX_VALUE ?
 					"unlimited" : String.valueOf(FixedBackOff.this.maxAttempts));
-			sb.append(", currentAttempts=").append(this.currentAttempts);
-			sb.append(", maxAttempts=").append(attemptValue);
-			sb.append('}');
-			return sb.toString();
+			return "FixedBackOff{interval=" + FixedBackOff.this.interval +
+					", currentAttempts=" + this.currentAttempts +
+					", maxAttempts=" + attemptValue +
+					'}';
 		}
 	}
 
diff --git a/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java b/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java
index ea41d5d1709..a78bc26f7c3 100644
--- a/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java
+++ b/spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java
@@ -53,7 +53,7 @@ final class HierarchicalUriComponents extends UriComponents {
 
 	private static final char PATH_DELIMITER = '/';
 
-	private static final String PATH_DELIMITER_STRING = "/";
+	private static final String PATH_DELIMITER_STRING = String.valueOf(PATH_DELIMITER);
 
 	private static final MultiValueMap<String, String> EMPTY_QUERY_PARAMS =
 			CollectionUtils.unmodifiableMultiValueMap(new LinkedMultiValueMap<>());
@@ -916,7 +916,7 @@ final class HierarchicalUriComponents extends UriComponents {
 
 		@Override
 		public String getPath() {
-			String delimiter = String.valueOf(PATH_DELIMITER);
+			String delimiter = PATH_DELIMITER_STRING;
 			StringJoiner pathBuilder = new StringJoiner(delimiter, delimiter, "");
 			for (String pathSegment : this.pathSegments) {
 				pathBuilder.add(pathSegment);
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/CachingResourceResolver.java b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/CachingResourceResolver.java
index 6125120b69a..515fe6fdca5 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/resource/CachingResourceResolver.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/resource/CachingResourceResolver.java
@@ -122,15 +122,13 @@ public class CachingResourceResolver extends AbstractResourceResolver {
 	}
 
 	protected String computeKey(@Nullable ServerWebExchange exchange, String requestPath) {
-		StringBuilder key = new StringBuilder(RESOLVED_RESOURCE_CACHE_KEY_PREFIX);
-		key.append(requestPath);
 		if (exchange != null) {
 			String codingKey = getContentCodingKey(exchange);
 			if (StringUtils.hasText(codingKey)) {
-				key.append("+encoding=").append(codingKey);
+				return RESOLVED_RESOURCE_CACHE_KEY_PREFIX + requestPath + "+encoding=" + codingKey;
 			}
 		}
-		return key.toString();
+		return RESOLVED_RESOURCE_CACHE_KEY_PREFIX + requestPath;
 	}
 
 	@Nullable
diff --git a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/CachingResourceResolver.java b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/CachingResourceResolver.java
index 0275e4a66de..23408a2a52c 100644
--- a/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/CachingResourceResolver.java
+++ b/spring-webmvc/src/main/java/org/springframework/web/servlet/resource/CachingResourceResolver.java
@@ -127,15 +127,13 @@ public class CachingResourceResolver extends AbstractResourceResolver {
 	}
 
 	protected String computeKey(@Nullable HttpServletRequest request, String requestPath) {
-		StringBuilder key = new StringBuilder(RESOLVED_RESOURCE_CACHE_KEY_PREFIX);
-		key.append(requestPath);
 		if (request != null) {
 			String codingKey = getContentCodingKey(request);
 			if (StringUtils.hasText(codingKey)) {
-				key.append("+encoding=").append(codingKey);
+				return RESOLVED_RESOURCE_CACHE_KEY_PREFIX + requestPath + "+encoding=" + codingKey;
 			}
 		}
-		return key.toString();
+		return RESOLVED_RESOURCE_CACHE_KEY_PREFIX + requestPath;
 	}
 
 	@Nullable