diff --git a/spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/context/properties/ConfigurationPropertiesReportEndpointProxyTests.java b/spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/context/properties/ConfigurationPropertiesReportEndpointProxyTests.java
index a5adf3997d7..469d761c6ed 100644
--- a/spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/context/properties/ConfigurationPropertiesReportEndpointProxyTests.java
+++ b/spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/context/properties/ConfigurationPropertiesReportEndpointProxyTests.java
@@ -91,7 +91,7 @@ public class ConfigurationPropertiesReportEndpointProxyTests {
 
 	}
 
-	public static abstract class AbstractExecutor implements Executor {
+	public abstract static class AbstractExecutor implements Executor {
 
 	}
 
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/cache/AbstractCacheAutoConfigurationTests.java b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/cache/AbstractCacheAutoConfigurationTests.java
index 59521bcf0dc..32e34136b1d 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/cache/AbstractCacheAutoConfigurationTests.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/cache/AbstractCacheAutoConfigurationTests.java
@@ -147,7 +147,7 @@ abstract class AbstractCacheAutoConfigurationTests {
 
 	}
 
-	static abstract class CacheManagerTestCustomizer<T extends CacheManager>
+	abstract static class CacheManagerTestCustomizer<T extends CacheManager>
 			implements CacheManagerCustomizer<T> {
 
 		T cacheManager;
diff --git a/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/SilentExitExceptionHandlerTests.java b/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/SilentExitExceptionHandlerTests.java
index 2d9b6b1a92e..7f4f01a37e1 100644
--- a/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/SilentExitExceptionHandlerTests.java
+++ b/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/restart/SilentExitExceptionHandlerTests.java
@@ -76,7 +76,7 @@ public class SilentExitExceptionHandlerTests {
 
 	}
 
-	private static abstract class TestThread extends Thread {
+	private abstract static class TestThread extends Thread {
 
 		private Throwable thrown;
 
diff --git a/spring-boot-project/spring-boot-parent/src/checkstyle/checkstyle.xml b/spring-boot-project/spring-boot-parent/src/checkstyle/checkstyle.xml
index b311494295e..1fd5ef714fd 100644
--- a/spring-boot-project/spring-boot-parent/src/checkstyle/checkstyle.xml
+++ b/spring-boot-project/spring-boot-parent/src/checkstyle/checkstyle.xml
@@ -129,6 +129,8 @@
 
 		<!-- Modifiers -->
 		<module name="com.puppycrawl.tools.checkstyle.checks.modifier.RedundantModifierCheck" />
+		<module name="com.puppycrawl.tools.checkstyle.checks.modifier.ModifierOrderCheck"/>
+
 
 		<!-- Regexp -->
  		<module name="com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineJavaCheck">
diff --git a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests.java b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests.java
index e48d9ef3455..52b1488bb3d 100644
--- a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests.java
+++ b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests.java
@@ -88,7 +88,7 @@ public abstract class AbstractSpringBootTestEmbeddedReactiveWebEnvironmentTests
 		assertThat(this.value).isEqualTo(123);
 	}
 
-	protected static abstract class AbstractConfig {
+	protected abstract static class AbstractConfig {
 
 		@Value("${server.port:8080}")
 		private int port = 8080;
diff --git a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestWebServerWebEnvironmentTests.java b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestWebServerWebEnvironmentTests.java
index 96663e30a3f..02036a393e6 100644
--- a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestWebServerWebEnvironmentTests.java
+++ b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/AbstractSpringBootTestWebServerWebEnvironmentTests.java
@@ -92,7 +92,7 @@ public abstract class AbstractSpringBootTestWebServerWebEnvironmentTests {
 				WebApplicationContextUtils.getWebApplicationContext(this.servletContext));
 	}
 
-	protected static abstract class AbstractConfig {
+	protected abstract static class AbstractConfig {
 
 		@Value("${server.port:8080}")
 		private int port = 8080;
diff --git a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/GsonTesterTests.java b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/GsonTesterTests.java
index 69e19142a31..7adbcd69f6a 100644
--- a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/GsonTesterTests.java
+++ b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/GsonTesterTests.java
@@ -65,7 +65,7 @@ public class GsonTesterTests extends AbstractJsonMarshalTesterTests {
 		return new GsonTester<>(resourceLoadClass, type, new GsonBuilder().create());
 	}
 
-	static abstract class InitFieldsBaseClass {
+	abstract static class InitFieldsBaseClass {
 
 		public GsonTester<ExampleObject> base;
 
diff --git a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JacksonTesterTests.java b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JacksonTesterTests.java
index 08db300c9b6..14b3446b516 100644
--- a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JacksonTesterTests.java
+++ b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JacksonTesterTests.java
@@ -64,7 +64,7 @@ public class JacksonTesterTests extends AbstractJsonMarshalTesterTests {
 		return new JacksonTester<>(resourceLoadClass, type, new ObjectMapper());
 	}
 
-	static abstract class InitFieldsBaseClass {
+	abstract static class InitFieldsBaseClass {
 
 		public JacksonTester<ExampleObject> base;
 
diff --git a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JsonbTesterTests.java b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JsonbTesterTests.java
index 91bd5987edf..80dff0d72ea 100644
--- a/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JsonbTesterTests.java
+++ b/spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/json/JsonbTesterTests.java
@@ -66,7 +66,7 @@ public class JsonbTesterTests extends AbstractJsonMarshalTesterTests {
 		return new JsonbTester<>(resourceLoadClass, type, JsonbBuilder.create());
 	}
 
-	static abstract class InitFieldsBaseClass {
+	abstract static class InitFieldsBaseClass {
 
 		public JsonbTester<ExampleObject> base;
 
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/Verify.java b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/Verify.java
index 84af1060f89..02dd5c76945 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/Verify.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/Verify.java
@@ -167,7 +167,7 @@ public final class Verify {
 
 	}
 
-	private static abstract class AbstractArchiveVerification {
+	private abstract static class AbstractArchiveVerification {
 
 		private final File file;
 
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/util/LambdaSafe.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/util/LambdaSafe.java
index 390cbd5c387..04bd7c8430a 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/util/LambdaSafe.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/util/LambdaSafe.java
@@ -100,7 +100,7 @@ public final class LambdaSafe {
 	/**
 	 * Abstract base class for lambda safe callbacks.
 	 */
-	private static abstract class LambdaSafeCallback<C, A, SELF extends LambdaSafeCallback<C, A, SELF>> {
+	private abstract static class LambdaSafeCallback<C, A, SELF extends LambdaSafeCallback<C, A, SELF>> {
 
 		private final Class<C> callbackType;
 
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java
index 7b7d20a6579..bfb81fa700a 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java
@@ -1357,7 +1357,7 @@ public class SpringApplicationTests {
 
 	}
 
-	static abstract class AbstractTestRunner implements ApplicationContextAware, Ordered {
+	abstract static class AbstractTestRunner implements ApplicationContextAware, Ordered {
 
 		private final String[] expectedBefore;
 
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/jackson/JsonComponentModuleTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/jackson/JsonComponentModuleTests.java
index 5e8ef910615..4887d08773c 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/jackson/JsonComponentModuleTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/jackson/JsonComponentModuleTests.java
@@ -110,7 +110,7 @@ public class JsonComponentModuleTests {
 	@JsonComponent
 	static class ComponentWithInnerAbstractClass {
 
-		private static abstract class AbstractSerializer
+		private abstract static class AbstractSerializer
 				extends NameAndAgeJsonComponent.Serializer {
 
 		}