diff --git a/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/AbstractReactiveHealthIndicator.java b/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/AbstractReactiveHealthIndicator.java
index 4e9269af24a..0b6e2c79269 100644
--- a/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/AbstractReactiveHealthIndicator.java
+++ b/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/AbstractReactiveHealthIndicator.java
@@ -99,7 +99,7 @@ public abstract class AbstractReactiveHealthIndicator implements ReactiveHealthI
 	}
 
 	/**
-	 * Actual health check logic. If an error occurs in the pipeline it will be handled
+	 * Actual health check logic. If an error occurs in the pipeline, it will be handled
 	 * automatically.
 	 * @param builder the {@link Health.Builder} to report health status and details
 	 * @return a {@link Mono} that provides the {@link Health}
diff --git a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/filter/AnnotationCustomizableTypeExcludeFilter.java b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/filter/AnnotationCustomizableTypeExcludeFilter.java
index 94640ff18f6..af92b8a1541 100644
--- a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/filter/AnnotationCustomizableTypeExcludeFilter.java
+++ b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/filter/AnnotationCustomizableTypeExcludeFilter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -119,8 +119,7 @@ public abstract class AnnotationCustomizableTypeExcludeFilter extends TypeExclud
 			return false;
 		}
 		AnnotationCustomizableTypeExcludeFilter other = (AnnotationCustomizableTypeExcludeFilter) obj;
-		boolean result = true;
-		result = result && hasAnnotation() == other.hasAnnotation();
+		boolean result = hasAnnotation() == other.hasAnnotation();
 		for (FilterType filterType : FilterType.values()) {
 			result &= ObjectUtils.nullSafeEquals(getFilters(filterType), other.getFilters(filterType));
 		}
diff --git a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/AutoConfigureTestDatabase.java b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/AutoConfigureTestDatabase.java
index e79b78ec0f4..9bed2317ed5 100644
--- a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/AutoConfigureTestDatabase.java
+++ b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/AutoConfigureTestDatabase.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -58,7 +58,7 @@ public @interface AutoConfigureTestDatabase {
 
 	/**
 	 * The type of connection to be established when {@link #replace() replacing} the
-	 * DataSource. By default will attempt to detect the connection based on the
+	 * DataSource. By default, will attempt to detect the connection based on the
 	 * classpath.
 	 * @return the type of connection to use
 	 */
diff --git a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/TestDatabaseAutoConfiguration.java b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/TestDatabaseAutoConfiguration.java
index b2b63c886a3..c0c28e124cc 100644
--- a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/TestDatabaseAutoConfiguration.java
+++ b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/jdbc/TestDatabaseAutoConfiguration.java
@@ -163,11 +163,6 @@ public class TestDatabaseAutoConfiguration {
 			return EmbeddedDatabase.class;
 		}
 
-		@Override
-		public boolean isSingleton() {
-			return true;
-		}
-
 	}
 
 	static class EmbeddedDataSourceFactory {
diff --git a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/AnnotationsPropertySource.java b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/AnnotationsPropertySource.java
index 5987729cd8b..a108e65b8c2 100644
--- a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/AnnotationsPropertySource.java
+++ b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/AnnotationsPropertySource.java
@@ -91,7 +91,7 @@ public class AnnotationsPropertySource extends EnumerablePropertySource<Class<?>
 			return;
 		}
 		Optional<Object> value = annotation.getValue(attribute.getName());
-		if (!value.isPresent()) {
+		if (value.isEmpty()) {
 			return;
 		}
 		if (skip == SkipPropertyMapping.ON_DEFAULT_VALUE) {
diff --git a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/PropertyMappingContextCustomizer.java b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/PropertyMappingContextCustomizer.java
index 2dde81b33d7..7598ae4b459 100644
--- a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/PropertyMappingContextCustomizer.java
+++ b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/PropertyMappingContextCustomizer.java
@@ -98,7 +98,7 @@ class PropertyMappingContextCustomizer implements ContextCustomizer {
 		private String getAnnotationsDescription(Set<Class<?>> annotations) {
 			StringBuilder result = new StringBuilder();
 			for (Class<?> annotation : annotations) {
-				if (result.length() != 0) {
+				if (!result.isEmpty()) {
 					result.append(", ");
 				}
 				result.append('@').append(ClassUtils.getShortName(annotation));
diff --git a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/servlet/WebDriverScope.java b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/servlet/WebDriverScope.java
index 4f9f1ae548f..ec04e6a986f 100644
--- a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/servlet/WebDriverScope.java
+++ b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/servlet/WebDriverScope.java
@@ -107,7 +107,7 @@ public class WebDriverScope implements Scope {
 
 	/**
 	 * Register this scope with the specified context and reassign appropriate bean
-	 * definitions to used it.
+	 * definitions to use it.
 	 * @param context the application context
 	 */
 	static void registerWith(ConfigurableApplicationContext context) {
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java
index fe2d6ac64d8..0531c28bab0 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java
@@ -570,8 +570,8 @@ public class SpringApplication {
 	}
 
 	/**
-	 * Apply any relevant post processing the {@link ApplicationContext}. Subclasses can
-	 * apply additional processing as required.
+	 * Apply any relevant post-processing to the {@link ApplicationContext}. Subclasses
+	 * can apply additional processing as required.
 	 * @param context the application context
 	 */
 	protected void postProcessApplicationContext(ConfigurableApplicationContext context) {