Cleanup kotlin sources

1. remove unused imports
2. remove redundant semicolon
3. remove empty class body
4. remove redundant 'constructor' keyword
5. remove redundant 'Unit' return type
6. use non-null type if possible

See gh-38708

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/data/sql/h2webconsole/springsecurity/DevProfileSecurityConfiguration.kt

@@ -40,7 +40,7 @@ class DevProfileSecurityConfiguration {
 
 	// tag::customizer[]
 	private fun <T> yourCustomAuthorization(): Customizer<T> {
-		return Customizer.withDefaults<T>()
+		return Customizer.withDefaults()
 	}
 	// end::customizer[]
 

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/externalconfig/typesafeconfigurationproperties/validate/nested/MyProperties.kt

@@ -29,7 +29,7 @@ class MyProperties {
 
 	var remoteAddress: @NotNull InetAddress? = null
 
-	val security: @Valid Security? = Security()
+	val security: @Valid Security = Security()
 
 	class Security {
 		var username: @NotEmpty String? = null

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testcontainers/atdevelopmenttime/devtools/MyContainersConfiguration.kt

@@ -17,7 +17,7 @@ package org.springframework.boot.docs.features.testcontainers.atdevelopmenttime.
 
 import org.springframework.boot.devtools.restart.RestartScope
 import org.springframework.boot.test.context.TestConfiguration
-import org.springframework.boot.testcontainers.service.connection.ServiceConnection;
+import org.springframework.boot.testcontainers.service.connection.ServiceConnection
 import org.springframework.context.annotation.Bean
 import org.testcontainers.containers.MongoDBContainer
 

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testcontainers/atdevelopmenttime/dynamicproperties/MyContainersConfiguration.kt

@@ -17,7 +17,7 @@
 package org.springframework.boot.docs.features.testcontainers.atdevelopmenttime.dynamicproperties
 
 import org.springframework.boot.test.context.TestConfiguration
-import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Bean
 import org.springframework.test.context.DynamicPropertyRegistry
 import org.testcontainers.containers.MongoDBContainer
 
@@ -27,8 +27,8 @@ class MyContainersConfiguration {
 	@Bean
 	fun monogDbContainer(properties: DynamicPropertyRegistry): MongoDBContainer {
 		var container = MongoDBContainer("mongo:5.0")
-		properties.add("spring.data.mongodb.host", container::getHost);
-		properties.add("spring.data.mongodb.port", container::getFirstMappedPort);
+		properties.add("spring.data.mongodb.host", container::getHost)
+		properties.add("spring.data.mongodb.port", container::getFirstMappedPort)
 		return container
 	}
 

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testcontainers/atdevelopmenttime/importingcontainerdeclarations/MyContainersConfiguration.kt

@@ -21,6 +21,4 @@ import org.springframework.boot.testcontainers.context.ImportTestcontainers
 
 @TestConfiguration(proxyBeanMethods = false)
 @ImportTestcontainers(MyContainers::class)
-class MyContainersConfiguration {
-
-}
+class MyContainersConfiguration

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testing/springbootapplications/autoconfiguredrestclient/MyRestClientTests.kt

@@ -31,7 +31,7 @@ class MyRestClientTests(
 	@Autowired val server: MockRestServiceServer) {
 
 	@Test
-	fun getVehicleDetailsWhenResultIsSuccessShouldReturnDetails(): Unit {
+	fun getVehicleDetailsWhenResultIsSuccessShouldReturnDetails() {
 		server.expect(MockRestRequestMatchers.requestTo("/greet/details"))
 			.andRespond(MockRestResponseCreators.withSuccess("hello", MediaType.TEXT_PLAIN))
 		val greeting = service.callRestService()

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testing/springbootapplications/userconfigurationandslicing/MyMongoConfiguration.kt

@@ -17,7 +17,7 @@
 package org.springframework.boot.docs.features.testing.springbootapplications.userconfigurationandslicing
 
 import org.springframework.context.annotation.Configuration
-import org.springframework.data.mongodb.config.EnableMongoAuditing;
+import org.springframework.data.mongodb.config.EnableMongoAuditing
 
 @Configuration(proxyBeanMethods = false)
 @EnableMongoAuditing

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testing/springbootapplications/usingmain/always/MyApplicationTests.kt

@@ -19,7 +19,6 @@ package org.springframework.boot.docs.features.testing.springbootapplications.us
 import org.junit.jupiter.api.Test
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.boot.test.context.SpringBootTest.UseMainMethod
-import org.springframework.context.annotation.Import
 
 @SpringBootTest(useMainMethod = UseMainMethod.ALWAYS)
 class MyApplicationTests {

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testing/springbootapplications/usingmain/custom/MyApplication.kt

@@ -26,6 +26,6 @@ class MyApplication
 fun main(args: Array<String>) {
 	runApplication<MyApplication>(*args) {
 		setBannerMode(Banner.Mode.OFF)
-		setAdditionalProfiles("myprofile");
+		setAdditionalProfiles("myprofile")
 	}
 }

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/features/testing/testcontainers/serviceconnections/MyRedisConfiguration.kt

@@ -18,7 +18,7 @@ package org.springframework.boot.docs.features.testing.testcontainers.servicecon
 
 import org.springframework.boot.test.context.TestConfiguration
 import org.springframework.boot.testcontainers.service.connection.ServiceConnection
-import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Bean
 import org.testcontainers.containers.GenericContainer
 
 @TestConfiguration(proxyBeanMethods = false)

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/web/graphql/runtimewiring/GreetingController.kt

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.docs.web.graphql.runtimewiring;
+package org.springframework.boot.docs.web.graphql.runtimewiring
 
 import org.springframework.graphql.data.method.annotation.Argument
 import org.springframework.graphql.data.method.annotation.QueryMapping

spring-boot-project/spring-boot-docs/src/main/kotlin/org/springframework/boot/docs/web/security/springwebflux/MyWebFluxSecurityConfiguration.kt

@@ -19,7 +19,6 @@ package org.springframework.boot.docs.web.security.springwebflux
 import org.springframework.boot.autoconfigure.security.reactive.PathRequest
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
-import org.springframework.security.config.Customizer
 import org.springframework.security.config.Customizer.withDefaults
 import org.springframework.security.config.web.server.ServerHttpSecurity
 import org.springframework.security.web.server.SecurityWebFilterChain