diff --git a/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatServerProperties.java b/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatServerProperties.java
index 8cbcc61ec9f..c895e25528d 100644
--- a/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatServerProperties.java
+++ b/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatServerProperties.java
@@ -697,7 +697,7 @@ public class TomcatServerProperties {
 		/**
 		 * Maximum size of the static resource cache.
 		 */
-		private @Nullable DataSize cacheMaxSize;
+		private DataSize cacheMaxSize = DataSize.ofMegabytes(10);
 
 		/**
 		 * Time-to-live of the static resource cache.
@@ -712,11 +712,11 @@ public class TomcatServerProperties {
 			this.allowCaching = allowCaching;
 		}
 
-		public @Nullable DataSize getCacheMaxSize() {
+		public DataSize getCacheMaxSize() {
 			return this.cacheMaxSize;
 		}
 
-		public void setCacheMaxSize(@Nullable DataSize cacheMaxSize) {
+		public void setCacheMaxSize(DataSize cacheMaxSize) {
 			this.cacheMaxSize = cacheMaxSize;
 		}
 
diff --git a/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizer.java b/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizer.java
index ca835acb471..b067915ae70 100644
--- a/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizer.java
+++ b/module/spring-boot-tomcat/src/main/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizer.java
@@ -380,14 +380,12 @@ public class TomcatWebServerFactoryCustomizer
 		factory.addContextCustomizers((context) -> context.addLifecycleListener((event) -> {
 			if (event.getType().equals(Lifecycle.CONFIGURE_START_EVENT)) {
 				context.getResources().setCachingAllowed(resource.isAllowCaching());
+				long cacheMaxSize = resource.getCacheMaxSize().toKilobytes();
+				context.getResources().setCacheMaxSize(cacheMaxSize);
 				if (resource.getCacheTtl() != null) {
 					long ttl = resource.getCacheTtl().toMillis();
 					context.getResources().setCacheTtl(ttl);
 				}
-				if (resource.getCacheMaxSize() != null) {
-					long cacheMaxSize = resource.getCacheMaxSize().toKilobytes();
-					context.getResources().setCacheMaxSize(cacheMaxSize);
-				}
 			}
 		}));
 	}
diff --git a/module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizerTests.java b/module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizerTests.java
index 8b8c203b529..8f9e9446db3 100644
--- a/module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizerTests.java
+++ b/module/spring-boot-tomcat/src/test/java/org/springframework/boot/tomcat/autoconfigure/TomcatWebServerFactoryCustomizerTests.java
@@ -322,6 +322,18 @@ class TomcatWebServerFactoryCustomizerTests {
 		assertThat(remoteIpValve.getTrustedProxies()).isEqualTo("proxy1|proxy2");
 	}
 
+	@Test
+	void resourceCacheMatchesDefault() {
+		TomcatServerProperties properties = new TomcatServerProperties();
+		customizeAndRunServer((server) -> {
+			Tomcat tomcat = server.getTomcat();
+			Context context = (Context) tomcat.getHost().findChildren()[0];
+			assertThat(properties.getResource().isAllowCaching()).isEqualTo(context.getResources().isCachingAllowed());
+			assertThat(properties.getResource().getCacheMaxSize())
+				.isEqualTo(DataSize.ofKilobytes(context.getResources().getCacheMaxSize()));
+		});
+	}
+
 	@Test
 	void customStaticResourceAllowCaching() {
 		bind("server.tomcat.resource.allow-caching=false");
@@ -334,7 +346,7 @@ class TomcatWebServerFactoryCustomizerTests {
 
 	@Test
 	void customStaticResourceCacheMaxSize() {
-		bind("server.tomcat.resource.cache-max-size=4096KB");
+		bind("server.tomcat.resource.cache-max-size=4MB");
 		customizeAndRunServer((server) -> {
 			Tomcat tomcat = server.getTomcat();
 			Context context = (Context) tomcat.getHost().findChildren()[0];