diff --git a/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleHttpCodeStatusMapper.java b/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleHttpCodeStatusMapper.java
index 934c36b6f6..9f4f9321e6 100644
--- a/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleHttpCodeStatusMapper.java
+++ b/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleHttpCodeStatusMapper.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -81,7 +81,8 @@ public class SimpleHttpCodeStatusMapper implements HttpCodeStatusMapper {
 			return null;
 		}
 		StringBuilder builder = new StringBuilder();
-		for (char ch : code.toCharArray()) {
+		for (int i = 0; i < code.length(); i++) {
+			char ch = code.charAt(i);
 			if (Character.isAlphabetic(ch) || Character.isDigit(ch)) {
 				builder.append(Character.toLowerCase(ch));
 			}
diff --git a/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleStatusAggregator.java b/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleStatusAggregator.java
index 42d200bcb3..4c5b9efe79 100644
--- a/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleStatusAggregator.java
+++ b/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/SimpleStatusAggregator.java
@@ -89,7 +89,8 @@ public class SimpleStatusAggregator implements StatusAggregator {
 			return null;
 		}
 		StringBuilder builder = new StringBuilder();
-		for (char ch : code.toCharArray()) {
+		for (int i = 0; i < code.length(); i++) {
+			char ch = code.charAt(i);
 			if (Character.isAlphabetic(ch) || Character.isDigit(ch)) {
 				builder.append(Character.toLowerCase(ch));
 			}
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/metadata/ConfigurationMetadata.java b/spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/metadata/ConfigurationMetadata.java
index 7d3c9ce278..1281954f59 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/metadata/ConfigurationMetadata.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/metadata/ConfigurationMetadata.java
@@ -189,7 +189,8 @@ public class ConfigurationMetadata {
 	static String toDashedCase(String name) {
 		StringBuilder dashed = new StringBuilder();
 		Character previous = null;
-		for (char current : name.toCharArray()) {
+		for (int i = 0; i < name.length(); i++) {
+			char current = name.charAt(i);
 			if (SEPARATORS.contains(current)) {
 				dashed.append("-");
 			}
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/ConfigTreePropertySource.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/ConfigTreePropertySource.java
index fd71316ee3..222a426461 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/ConfigTreePropertySource.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/ConfigTreePropertySource.java
@@ -308,7 +308,8 @@ public class ConfigTreePropertySource extends EnumerablePropertySource<Path> imp
 				return string;
 			}
 			int numberOfLines = 0;
-			for (char ch : string.toCharArray()) {
+			for (int i = 0; i < string.length(); i++) {
+				char ch = string.charAt(i);
 				if (ch == '\n') {
 					numberOfLines++;
 				}