diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ResourceProperties.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ResourceProperties.java
index 7f2591f33f..7f916334fa 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ResourceProperties.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ResourceProperties.java
@@ -23,6 +23,7 @@ import java.util.concurrent.TimeUnit;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.boot.context.properties.bind.convert.DefaultDurationUnit;
+import org.springframework.http.CacheControl;
 
 /**
  * Properties used to configure resource handling.
@@ -458,9 +459,9 @@ public class ResourceProperties {
 				this.sMaxAge = sMaxAge;
 			}
 
-			public org.springframework.http.CacheControl toHttpCacheControl() {
+			public CacheControl toHttpCacheControl() {
 				PropertyMapper map = PropertyMapper.get();
-				org.springframework.http.CacheControl control = createCacheControl();
+				CacheControl control = createCacheControl();
 				map.from(this::getMustRevalidate).whenTrue()
 						.toCall(control::mustRevalidate);
 				map.from(this::getNoTransform).whenTrue().toCall(control::noTransform);
@@ -478,18 +479,18 @@ public class ResourceProperties {
 				return control;
 			}
 
-			private org.springframework.http.CacheControl createCacheControl() {
+			private CacheControl createCacheControl() {
 				if (Boolean.TRUE.equals(this.noStore)) {
-					return org.springframework.http.CacheControl.noStore();
+					return CacheControl.noStore();
 				}
 				if (Boolean.TRUE.equals(this.noCache)) {
-					return org.springframework.http.CacheControl.noCache();
+					return CacheControl.noCache();
 				}
 				if (this.maxAge != null) {
-					return org.springframework.http.CacheControl
+					return CacheControl
 							.maxAge(this.maxAge.getSeconds(), TimeUnit.SECONDS);
 				}
-				return org.springframework.http.CacheControl.empty();
+				return CacheControl.empty();
 			}
 
 		}
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfigurationTests.java b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfigurationTests.java
index c1579079ff..0299e944ba 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfigurationTests.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jackson/JacksonAutoConfigurationTests.java
@@ -22,7 +22,6 @@ import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.HashSet;
 import java.util.Set;
-import java.util.TimeZone;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonCreator.Mode;
@@ -457,7 +456,7 @@ public class JacksonAutoConfigurationTests {
 		ObjectMapper mapper = this.context.getBean(ObjectMapper.class);
 		DateTime dateTime = new DateTime(1988, 6, 25, 20, 30, DateTimeZone.UTC);
 		String expected = FormatConfig.DEFAULT_DATETIME_PRINTER.rawFormatter()
-				.withZone(DateTimeZone.forTimeZone(TimeZone.getTimeZone("UTC")))
+				.withZone(DateTimeZone.UTC)
 				.print(dateTime);
 		assertThat(mapper.writeValueAsString(dateTime)).isEqualTo("\"" + expected + "\"");
 	}
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ResourcePropertiesTests.java b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ResourcePropertiesTests.java
index 6e490c06a0..83c117ad76 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ResourcePropertiesTests.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ResourcePropertiesTests.java
@@ -22,6 +22,7 @@ import org.junit.Test;
 
 import org.springframework.boot.autoconfigure.web.ResourceProperties.Cache;
 import org.springframework.boot.testsupport.assertj.Matched;
+import org.springframework.http.CacheControl;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.hamcrest.CoreMatchers.endsWith;
@@ -73,7 +74,7 @@ public class ResourcePropertiesTests {
 
 	@Test
 	public void emptyCacheControl() {
-		org.springframework.http.CacheControl cacheControl = this.properties.getCache()
+		CacheControl cacheControl = this.properties.getCache()
 				.getCachecontrol().toHttpCacheControl();
 		assertThat(cacheControl.getHeaderValue()).isNull();
 	}
@@ -90,8 +91,7 @@ public class ResourcePropertiesTests {
 		properties.setSMaxAge(Duration.ofSeconds(5));
 		properties.setStaleIfError(Duration.ofSeconds(6));
 		properties.setStaleWhileRevalidate(Duration.ofSeconds(7));
-		org.springframework.http.CacheControl cacheControl = properties
-				.toHttpCacheControl();
+		CacheControl cacheControl = properties.toHttpCacheControl();
 		assertThat(cacheControl.getHeaderValue()).isEqualTo(
 				"max-age=4, must-revalidate, no-transform, public, private, proxy-revalidate,"
 						+ " s-maxage=5, stale-if-error=6, stale-while-revalidate=7");
@@ -102,8 +102,7 @@ public class ResourcePropertiesTests {
 		Cache.Cachecontrol properties = this.properties.getCache().getCachecontrol();
 		properties.setMaxAge(Duration.ofSeconds(4));
 		properties.setNoStore(true);
-		org.springframework.http.CacheControl cacheControl = properties
-				.toHttpCacheControl();
+		CacheControl cacheControl = properties.toHttpCacheControl();
 		assertThat(cacheControl.getHeaderValue()).isEqualTo("no-store");
 	}
 
diff --git a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/FilteredClassLoaderTests.java b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/FilteredClassLoaderTests.java
index 17ea64233a..dcbc3a298b 100644
--- a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/FilteredClassLoaderTests.java
+++ b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/FilteredClassLoaderTests.java
@@ -46,9 +46,13 @@ public class FilteredClassLoaderTests {
 	public void loadClassWhenFilteredOnClassShouldThrowClassNotFound() throws Exception {
 		FilteredClassLoader classLoader = new FilteredClassLoader(
 				FilteredClassLoaderTests.class);
-		this.thrown.expect(ClassNotFoundException.class);
-		classLoader.loadClass(getClass().getName());
-		classLoader.close();
+		try {
+			this.thrown.expect(ClassNotFoundException.class);
+			classLoader.loadClass(getClass().getName());
+		}
+		finally {
+			classLoader.close();
+		}
 	}
 
 	@Test
diff --git a/spring-boot-project/spring-boot-test/src/test/kotlin/org/springframework/boot/test/web/client/TestRestTemplateExtensionsTests.kt b/spring-boot-project/spring-boot-test/src/test/kotlin/org/springframework/boot/test/web/client/TestRestTemplateExtensionsTests.kt
index d9ae59c7fb..8239f05d10 100644
--- a/spring-boot-project/spring-boot-test/src/test/kotlin/org/springframework/boot/test/web/client/TestRestTemplateExtensionsTests.kt
+++ b/spring-boot-project/spring-boot-test/src/test/kotlin/org/springframework/boot/test/web/client/TestRestTemplateExtensionsTests.kt
@@ -72,7 +72,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `getForEntity with reified type parameters, String and URI`() {
+	fun `getForEntity with reified type parameters and URI`() {
 		val url = URI("https://spring.io")
 		template.getForEntity<Foo>(url)
 		verify(template, times(1)).getForEntity(url, Foo::class.java)
@@ -88,7 +88,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `getForEntity with reified type parameters and Map`() {
+	fun `getForEntity with reified type parameters, String and Map`() {
 		val url = "https://spring.io"
 		val vars = mapOf(Pair("key1", "value1"), Pair("key2", "value2"))
 		template.getForEntity<Foo>(url, vars)
@@ -96,7 +96,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `patchForObject with reified type parameters, String and varargs`() {
+	fun `patchForObject with reified type parameters, String, Any and varargs`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		val var1 = "var1"
@@ -106,7 +106,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `patchForObject with reified type parameters, String and Map`() {
+	fun `patchForObject with reified type parameters, String, Any and Map`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		val vars = mapOf(Pair("key1", "value1"), Pair("key2", "value2"))
@@ -115,7 +115,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `patchForObject with reified type parameters`() {
+	fun `patchForObject with reified type parameters, String and Any`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		template.patchForObject<Foo>(url, body)
@@ -123,7 +123,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `postForObject with reified type parameters, String and varargs`() {
+	fun `postForObject with reified type parameters, String, Any and varargs`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		val var1 = "var1"
@@ -133,7 +133,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `postForObject with reified type parameters, String and Map`() {
+	fun `postForObject with reified type parameters, String, Any and Map`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		val vars = mapOf(Pair("key1", "value1"), Pair("key2", "value2"))
@@ -142,7 +142,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `postForObject with reified type parameters`() {
+	fun `postForObject with reified type parameters, String and Any`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		template.postForObject<Foo>(url, body)
@@ -150,7 +150,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `postForEntity with reified type parameters, String and varargs`() {
+	fun `postForEntity with reified type parameters, String, Any and varargs`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		val var1 = "var1"
@@ -160,7 +160,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `postForEntity with reified type parameters, String and Map`() {
+	fun `postForEntity with reified type parameters, String, Any and Map`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		val vars = mapOf(Pair("key1", "value1"), Pair("key2", "value2"))
@@ -169,7 +169,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `postForEntity with reified type parameters`() {
+	fun `postForEntity with reified type parameters, String and Any`() {
 		val url = "https://spring.io"
 		val body: Any = "body"
 		template.postForEntity<Foo>(url, body)
@@ -210,7 +210,7 @@ class TestRestTemplateExtensionsTests {
 	}
 
 	@Test
-	fun `exchange with reified type parameters, String, HttpEntity`() {
+	fun `exchange with reified type parameters and HttpEntity`() {
 		val entity = mock<RequestEntity<Foo>>()
 		template.exchange<List<Foo>>(entity)
 		verify(template, times(1)).exchange(entity,
diff --git a/spring-boot-project/spring-boot/pom.xml b/spring-boot-project/spring-boot/pom.xml
index 6a106b9e21..8654c69ba2 100644
--- a/spring-boot-project/spring-boot/pom.xml
+++ b/spring-boot-project/spring-boot/pom.xml
@@ -267,12 +267,12 @@
 		</dependency>
 		<dependency>
 			<groupId>org.jetbrains.kotlin</groupId>
-			<artifactId>kotlin-stdlib</artifactId>
+			<artifactId>kotlin-reflect</artifactId>
 			<optional>true</optional>
 		</dependency>
 		<dependency>
 			<groupId>org.jetbrains.kotlin</groupId>
-			<artifactId>kotlin-reflect</artifactId>
+			<artifactId>kotlin-stdlib</artifactId>
 			<optional>true</optional>
 		</dependency>
 		<!-- Annotation processing -->
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/PropertyMapper.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/PropertyMapper.java
index 511fff9f22..7d05a2c4ef 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/PropertyMapper.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/PropertyMapper.java
@@ -29,7 +29,7 @@ import org.springframework.util.StringUtils;
 /**
  * Utility that can be used to map values from a supplied source to a destination.
  * Primarily intended to be help when mapping from
- * {@link ConfigurationProperties @ConfigrationProperties} to third-party classes.
+ * {@link ConfigurationProperties @ConfigurationProperties} to third-party classes.
  * <p>
  * Can filter values based on predicates and adapt values if needed. For example:
  * <pre class="code">
@@ -176,7 +176,7 @@ public final class PropertyMapper {
 		private final Predicate<T> predicate;
 
 		private Source(Supplier<T> supplier, Predicate<T> predicate) {
-			Assert.notNull(predicate, "Arse");
+			Assert.notNull(predicate, "Predicate must not be null");
 			this.supplier = supplier;
 			this.predicate = predicate;
 		}
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/convert/DurationConverter.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/convert/DurationConverter.java
index 1084a1fd67..916fd3dede 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/convert/DurationConverter.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/convert/DurationConverter.java
@@ -49,9 +49,9 @@ class DurationConverter implements GenericConverter {
 		TYPES = Collections.unmodifiableSet(types);
 	}
 
-	private static Pattern ISO8601 = Pattern.compile("^[\\+\\-]?P.*$");
+	private static final Pattern ISO8601 = Pattern.compile("^[\\+\\-]?P.*$");
 
-	private static Pattern SIMPLE = Pattern.compile("^([\\+\\-]?\\d+)([a-zA-Z]{0,2})$");
+	private static final Pattern SIMPLE = Pattern.compile("^([\\+\\-]?\\d+)([a-zA-Z]{0,2})$");
 
 	private static final Map<String, ChronoUnit> UNITS;
 
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/convert/DurationConverterTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/convert/DurationConverterTests.java
index 7742fea0d7..ccfc89ffb9 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/convert/DurationConverterTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/convert/DurationConverterTests.java
@@ -51,7 +51,6 @@ public class DurationConverterTests {
 		assertThat(convert("PT10H")).isEqualTo(Duration.parse("PT10H"));
 		assertThat(convert("P2D")).isEqualTo(Duration.parse("P2D"));
 		assertThat(convert("P2DT3H4M")).isEqualTo(Duration.parse("P2DT3H4M"));
-		assertThat(convert("P2DT3H4M")).isEqualTo(Duration.parse("P2DT3H4M"));
 		assertThat(convert("-PT6H3M")).isEqualTo(Duration.parse("-PT6H3M"));
 		assertThat(convert("-PT-6H+3M")).isEqualTo(Duration.parse("-PT-6H+3M"));
 	}