diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/DefaultReactiveWebServerFactoryCustomizer.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/DefaultReactiveWebServerFactoryCustomizer.java
index 519f0725aec..bac4b73803b 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/DefaultReactiveWebServerFactoryCustomizer.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/DefaultReactiveWebServerFactoryCustomizer.java
@@ -61,21 +61,21 @@ public class DefaultReactiveWebServerFactoryCustomizer
 
 	@Override
 	public void customize(ConfigurableReactiveWebServerFactory factory) {
-		PropertyMapper map = PropertyMapper.get();
-		map.from(this.serverProperties::getPort).whenNonNull().to(factory::setPort);
-		map.from(this.serverProperties::getAddress).whenNonNull().to(factory::setAddress);
-		map.from(this.serverProperties::getSsl).whenNonNull().to(factory::setSsl);
-		map.from(this.serverProperties::getCompression).whenNonNull().to(factory::setCompression);
-		map.from(this.serverProperties::getHttp2).whenNonNull().to(factory::setHttp2);
-		map.from(() -> factory).when(configurableReactiveWebServerFactory -> factory instanceof TomcatReactiveWebServerFactory)
-				.to(configurableReactiveWebServerFactory -> TomcatCustomizer.customizeTomcat(this.serverProperties, this.environment,
-						(TomcatReactiveWebServerFactory) factory));
-		map.from(() -> factory).when(configurableReactiveWebServerFactory -> factory instanceof JettyReactiveWebServerFactory)
-				.to(configurableReactiveWebServerFactory -> JettyCustomizer.customizeJetty(this.serverProperties, this.environment,
-						(JettyReactiveWebServerFactory) factory));
-		map.from(() -> factory).when(configurableReactiveWebServerFactory -> factory instanceof UndertowReactiveWebServerFactory)
-				.to(configurableReactiveWebServerFactory -> UndertowCustomizer.customizeUndertow(this.serverProperties, this.environment,
-						(UndertowReactiveWebServerFactory) factory));
+		PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
+		map.from(this.serverProperties::getPort).to(factory::setPort);
+		map.from(this.serverProperties::getAddress).to(factory::setAddress);
+		map.from(this.serverProperties::getSsl).to(factory::setSsl);
+		map.from(this.serverProperties::getCompression).to(factory::setCompression);
+		map.from(this.serverProperties::getHttp2).to(factory::setHttp2);
+		map.from(() -> factory).whenInstanceOf(TomcatReactiveWebServerFactory.class)
+				.to(tomcatFactory -> TomcatCustomizer.customizeTomcat(
+						this.serverProperties, this.environment, tomcatFactory));
+		map.from(() -> factory).whenInstanceOf(JettyReactiveWebServerFactory.class)
+				.to(jettyFactory -> JettyCustomizer.customizeJetty(this.serverProperties,
+						this.environment, jettyFactory));
+		map.from(() -> factory).whenInstanceOf(UndertowReactiveWebServerFactory.class)
+				.to(undertowFactory -> UndertowCustomizer.customizeUndertow(
+						this.serverProperties, this.environment, undertowFactory));
 	}
 
 }
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/DefaultServletWebServerFactoryCustomizer.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/DefaultServletWebServerFactoryCustomizer.java
index 4869b8d7e3d..8d696262296 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/DefaultServletWebServerFactoryCustomizer.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/DefaultServletWebServerFactoryCustomizer.java
@@ -69,30 +69,34 @@ public class DefaultServletWebServerFactoryCustomizer
 
 	@Override
 	public void customize(ConfigurableServletWebServerFactory factory) {
-		PropertyMapper map = PropertyMapper.get();
-		map.from(this.serverProperties::getPort).whenNonNull().to(factory::setPort);
-		map.from(this.serverProperties::getAddress).whenNonNull().to(factory::setAddress);
-		map.from(this.serverProperties.getServlet()::getContextPath).whenNonNull().to(factory::setContextPath);
-		map.from(this.serverProperties::getDisplayName).whenNonNull().to(factory::setDisplayName);
+		PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
+		map.from(this.serverProperties::getPort).to(factory::setPort);
+		map.from(this.serverProperties::getAddress).to(factory::setAddress);
+		map.from(this.serverProperties.getServlet()::getContextPath)
+				.to(factory::setContextPath);
+		map.from(this.serverProperties::getDisplayName).to(factory::setDisplayName);
 		map.from(this.serverProperties.getServlet()::getSession).to(factory::setSession);
-		map.from(this.serverProperties::getSsl).whenNonNull().to(factory::setSsl);
-		map.from(this.serverProperties::getServlet).whenNonNull().as(ServerProperties.Servlet::getJsp).to(factory::setJsp);
-		map.from(this.serverProperties::getCompression).whenNonNull().to(factory::setCompression);
-		map.from(this.serverProperties::getHttp2).whenNonNull().to(factory::setHttp2);
+		map.from(this.serverProperties::getSsl).to(factory::setSsl);
+		map.from(this.serverProperties::getServlet).as(ServerProperties.Servlet::getJsp)
+				.to(factory::setJsp);
+		map.from(this.serverProperties::getCompression).to(factory::setCompression);
+		map.from(this.serverProperties::getHttp2).to(factory::setHttp2);
 		map.from(this.serverProperties::getServerHeader).to(factory::setServerHeader);
-		map.from(() -> factory).when(configurableServletWebServerFactory -> factory instanceof TomcatServletWebServerFactory)
-				.to(configurableServletWebServerFactory -> {
-					TomcatServletWebServerFactory tomcatFactory = (TomcatServletWebServerFactory) factory;
-					TomcatCustomizer.customizeTomcat(this.serverProperties, this.environment, tomcatFactory);
-					TomcatServletCustomizer.customizeTomcat(this.serverProperties, this.environment, tomcatFactory);
+		map.from(() -> factory).whenInstanceOf(TomcatServletWebServerFactory.class)
+				.to(tomcatFactory -> {
+					TomcatCustomizer.customizeTomcat(this.serverProperties,
+							this.environment, tomcatFactory);
+					TomcatServletCustomizer.customizeTomcat(this.serverProperties,
+							this.environment, tomcatFactory);
 				});
-		map.from(() -> factory).when(configurableServletWebServerFactory -> factory instanceof JettyServletWebServerFactory)
-				.to(configurableServletWebServerFactory -> JettyCustomizer.customizeJetty(this.serverProperties, this.environment,
-						(JettyServletWebServerFactory) factory));
-		map.from(() -> factory).when(configurableServletWebServerFactory -> factory instanceof UndertowServletWebServerFactory)
-				.to(configurableServletWebServerFactory -> UndertowCustomizer.customizeUndertow(this.serverProperties, this.environment,
-						(UndertowServletWebServerFactory) factory));
-		map.from(this.serverProperties.getServlet()::getContextParameters).to(factory::setInitParameters);
+		map.from(() -> factory).whenInstanceOf(JettyServletWebServerFactory.class)
+				.to(jettyFactory -> JettyCustomizer.customizeJetty(this.serverProperties,
+						this.environment, jettyFactory));
+		map.from(() -> factory).whenInstanceOf(UndertowServletWebServerFactory.class)
+				.to(undertowFactory -> UndertowCustomizer.customizeUndertow(
+						this.serverProperties, this.environment, undertowFactory));
+		map.from(this.serverProperties.getServlet()::getContextParameters)
+				.to(factory::setInitParameters);
 	}
 
 	private static class TomcatServletCustomizer {