diff --git a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java
index 8105cc4502f1..bf228281cdb7 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java
@@ -167,8 +167,7 @@ private boolean hasConfigurationProcessorOnClasspath(JavaCompile compile) {
 				? compile.getOptions().getAnnotationProcessorPath().getFiles()
 				: compile.getClasspath().getFiles();
 		return files.stream().map(File::getName)
-				.filter((name) -> name.startsWith("spring-boot-configuration-processor"))
-				.findFirst().isPresent();
+				.anyMatch((name) -> name.startsWith("spring-boot-configuration-processor"));
 	}
 
 	private void configureAdditionalMetadataLocations(JavaCompile compile,
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SystemEnvironmentPropertyMapper.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SystemEnvironmentPropertyMapper.java
index 0dd392f5b6a2..2b3faa4c074d 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SystemEnvironmentPropertyMapper.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SystemEnvironmentPropertyMapper.java
@@ -16,8 +16,6 @@
 
 package org.springframework.boot.context.properties.source;
 
-import java.util.stream.IntStream;
-
 import org.springframework.boot.context.properties.source.ConfigurationPropertyName.Form;
 
 /**
@@ -95,7 +93,7 @@ private String convertLegacyName(ConfigurationPropertyName name) {
 	}
 
 	private Object convertLegacyNameElement(String element) {
-		return element.replace("-", "_").toUpperCase();
+		return element.replace('-', '_').toUpperCase();
 	}
 
 	private CharSequence processElementValue(CharSequence value) {
@@ -104,9 +102,7 @@ private CharSequence processElementValue(CharSequence value) {
 	}
 
 	private static boolean isNumber(String string) {
-		IntStream nonDigits = string.chars().filter((c) -> !Character.isDigit(c));
-		boolean hasNonDigit = nonDigits.findFirst().isPresent();
-		return !hasNonDigit;
+		return string.chars().allMatch(Character::isDigit);
 	}
 
 }