diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationSorter.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationSorter.java
index f8bebeea4568..2c1af6d5f74c 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationSorter.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationSorter.java
@@ -136,8 +136,8 @@ AutoConfigurationClass get(String className) {
 		}
 
 		Set<String> getClassesRequestedAfter(String className) {
-			Set<String> classesRequestedAfter = new LinkedHashSet<>();
-			classesRequestedAfter.addAll(get(className).getAfter());
+			Set<String> setOfClassesRequestedAfter = get(className).getAfter();
+			Set<String> classesRequestedAfter = new LinkedHashSet<>(setOfClassesRequestedAfter);
 			this.classes.forEach((name, autoConfigurationClass) -> {
 				if (autoConfigurationClass.getBefore().contains(className)) {
 					classesRequestedAfter.add(name);
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelector.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelector.java
index 6b5f546d93c1..ec52a64a8a04 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelector.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfigurationImportSelector.java
@@ -58,8 +58,8 @@ class ImportAutoConfigurationImportSelector extends AutoConfigurationImportSelec
 
 	@Override
 	public Set<Object> determineImports(AnnotationMetadata metadata) {
-		Set<String> result = new LinkedHashSet<>();
-		result.addAll(getCandidateConfigurations(metadata, null));
+		List<String> candidateConfigurations = getCandidateConfigurations(metadata, null);
+		Set<String> result = new LinkedHashSet<>(candidateConfigurations);
 		result.removeAll(getExclusions(metadata, null));
 		return Collections.unmodifiableSet(result);
 	}
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java
index ab70a9a9b5b7..665a6776f4a6 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/OnBeanCondition.java
@@ -376,9 +376,7 @@ private static Set<String> addAll(Set<String> result, String[] additional) {
 			return result;
 		}
 		result = (result != null) ? result : new LinkedHashSet<>();
-		for (String addition : additional) {
-			result.add(addition);
-		}
+		Collections.addAll(result, additional);
 		return result;
 	}
 
@@ -454,9 +452,7 @@ else if (value instanceof String) {
 		}
 
 		private void merge(Set<String> result, String... additional) {
-			for (String addition : additional) {
-				result.add(addition);
-			}
+			Collections.addAll(result, additional);
 		}
 
 		private Set<Class<?>> resolveWhenPossible(Set<String> classNames) {
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfiguration.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfiguration.java
index a4e6c7098e2d..0bad6a82765e 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfiguration.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/groovy/template/GroovyTemplateAutoConfiguration.java
@@ -102,10 +102,7 @@ private boolean isUsingGroovyAllJar() {
 			try {
 				ProtectionDomain domain = MarkupTemplateEngine.class.getProtectionDomain();
 				CodeSource codeSource = domain.getCodeSource();
-				if (codeSource != null && codeSource.getLocation().toString().contains("-all")) {
-					return true;
-				}
-				return false;
+				return codeSource != null && codeSource.getLocation().toString().contains("-all");
 			}
 			catch (Exception ex) {
 				return false;
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jmx/ParentAwareNamingStrategy.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jmx/ParentAwareNamingStrategy.java
index 1b5115debb2e..71b7e31f68a8 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jmx/ParentAwareNamingStrategy.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jmx/ParentAwareNamingStrategy.java
@@ -17,6 +17,7 @@
 package org.springframework.boot.autoconfigure.jmx;
 
 import java.util.Hashtable;
+import java.util.Map;
 
 import javax.management.MalformedObjectNameException;
 import javax.management.ObjectName;
@@ -57,8 +58,8 @@ public void setEnsureUniqueRuntimeObjectNames(boolean ensureUniqueRuntimeObjectN
 	@Override
 	public ObjectName getObjectName(Object managedBean, String beanKey) throws MalformedObjectNameException {
 		ObjectName name = super.getObjectName(managedBean, beanKey);
-		Hashtable<String, String> properties = new Hashtable<>();
-		properties.putAll(name.getKeyPropertyList());
+		Map<String, String> keyPropertyList = name.getKeyPropertyList();
+		Hashtable<String, String> properties = new Hashtable<>(keyPropertyList);
 		if (this.ensureUniqueRuntimeObjectNames) {
 			properties.put("identity", ObjectUtils.getIdentityHexString(managedBean));
 		}
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/DataSourceInitializedPublisher.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/DataSourceInitializedPublisher.java
index 8d9e2f73587e..29556fc9c69b 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/DataSourceInitializedPublisher.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/DataSourceInitializedPublisher.java
@@ -112,10 +112,7 @@ private boolean isInitializingDatabase(DataSource dataSource) {
 				: "none");
 		Map<String, Object> hibernate = this.hibernateProperties.determineHibernateProperties(
 				this.jpaProperties.getProperties(), new HibernateSettings().ddlAuto(defaultDdlAuto));
-		if (hibernate.containsKey("hibernate.hbm2ddl.auto")) {
-			return true;
-		}
-		return false;
+		return hibernate.containsKey("hibernate.hbm2ddl.auto");
 	}
 
 	/**
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/AutoConfigurationSorterTests.java b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/AutoConfigurationSorterTests.java
index 1ddbcca63d64..6d25109e9700 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/AutoConfigurationSorterTests.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/AutoConfigurationSorterTests.java
@@ -18,6 +18,7 @@
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Properties;
@@ -192,9 +193,7 @@ private String merge(Class<?>[] value, String[] name) {
 		for (Class<?> type : value) {
 			items.add(type.getName());
 		}
-		for (String type : name) {
-			items.add(type);
-		}
+		Collections.addAll(items, name);
 		return StringUtils.collectionToCommaDelimitedString(items);
 	}