diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc
index dd1fc99cd780..71036444ca4f 100644
--- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc
+++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc
@@ -6948,7 +6948,7 @@ You can use the `@DataJpaTest` annotation to test JPA applications.
 By default, it scans for `@Entity` classes and configures Spring Data JPA repositories.
 If an embedded database is available on the classpath, it configures one as well.
 SQL queries are logged by default by setting the `spring.jpa.show-sql` property to `true`.
-This can be disabled using the `showSql()` attribute of the annotation.
+This can be disabled by using the `showSql()` attribute of the annotation.
 
 Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataJpaTest` annotation is used.
 `@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans.
diff --git a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTest.java b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTest.java
index 26de93fdb150..fabffc964c33 100644
--- a/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTest.java
+++ b/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/orm/jpa/DataJpaTest.java
@@ -54,8 +54,8 @@
  * override these settings.
  * <p>
  * SQL queries are logged by default by setting the {@code spring.jpa.show-sql} property
- * to {@code true}. This can be disabled using the {@link DataJpaTest#showSql() showSql}
- * attribute.
+ * to {@code true}. This can be disabled by using the {@link DataJpaTest#showSql()
+ * showSql} attribute.
  * <p>
  * If you are looking to load your full application configuration, but use an embedded
  * database, you should consider {@link SpringBootTest @SpringBootTest} combined with
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/availability/ApplicationAvailabilityBean.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/availability/ApplicationAvailabilityBean.java
index cac11b347d2b..f565d61f637d 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/availability/ApplicationAvailabilityBean.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/availability/ApplicationAvailabilityBean.java
@@ -38,7 +38,7 @@
 public class ApplicationAvailabilityBean
 		implements ApplicationAvailability, ApplicationListener<AvailabilityChangeEvent<?>> {
 
-	private static final Log logger = LogFactory.getLog(ApplicationAvailability.class);
+	private static final Log logger = LogFactory.getLog(ApplicationAvailabilityBean.class);
 
 	private final Map<Class<? extends AvailabilityState>, AvailabilityChangeEvent<?>> events = new HashMap<>();
 
@@ -70,6 +70,13 @@ public void onApplicationEvent(AvailabilityChangeEvent<?> event) {
 	}
 
 	private void logStateChange(AvailabilityChangeEvent<?> event) {
+		if (logger.isInfoEnabled()) {
+			StringBuilder message = createStateChangeMessage(event);
+			logger.info(message);
+		}
+	}
+
+	private StringBuilder createStateChangeMessage(AvailabilityChangeEvent<?> event) {
 		Class<? extends AvailabilityState> stateType = getStateType(event.getState());
 		StringBuilder message = new StringBuilder(
 				"Application availability state " + stateType.getSimpleName() + " changed");
@@ -78,15 +85,16 @@ private void logStateChange(AvailabilityChangeEvent<?> event) {
 			message.append(" from " + lastChangeEvent.getState());
 		}
 		message.append(" to " + event.getState());
-		if (event.getSource() != null) {
-			if (event.getSource() instanceof Throwable) {
-				message.append(": " + event.getSource());
+		Object source = event.getSource();
+		if (source != null) {
+			if (source instanceof Throwable) {
+				message.append(": " + source);
 			}
-			else if (!(event.getSource() instanceof ApplicationEventPublisher)) {
-				message.append(": " + event.getSource().getClass().getName());
+			else if (!(source instanceof ApplicationEventPublisher)) {
+				message.append(": " + source.getClass().getName());
 			}
 		}
-		logger.info(message);
+		return message;
 	}
 
 	@SuppressWarnings("unchecked")
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/ApplicationConversionService.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/ApplicationConversionService.java
index 44329112b53b..06f49fe4daac 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/ApplicationConversionService.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/convert/ApplicationConversionService.java
@@ -55,7 +55,7 @@ public class ApplicationConversionService extends FormattingConversionService {
 
 	private static volatile ApplicationConversionService sharedInstance;
 
-	private boolean unmodifiable;
+	private final boolean unmodifiable;
 
 	public ApplicationConversionService() {
 		this(null);
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ReactiveWebServerFactoryTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ReactiveWebServerFactoryTests.java
index c1820a3fc74e..db8cee18ffb4 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ReactiveWebServerFactoryTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ReactiveWebServerFactoryTests.java
@@ -23,7 +23,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Tests for {@JettyReactiveWebServerFactory} with Jetty 10.
+ * Tests for {@link JettyReactiveWebServerFactory} with Jetty 10.
  *
  * @author Andy Wilkinson
  */
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java
index acf6f6ec150c..404200c96708 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/Jetty10ServletWebServerFactoryTests.java
@@ -23,7 +23,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Tests for {@JettyServletWebServerFactory} with Jetty 10.
+ * Tests for {@link JettyServletWebServerFactory} with Jetty 10.
  *
  * @author Andy Wilkinson
  */