Leverage @NullMarked instead of package configuration

This commit replaces NullAway package configuration by package-level
`@NullMarked` detection by configuring `NullAway:AnnotatedPackages` to
an empty string.

NullAway configuration should be refined to use a proper flag instead
once uber/NullAway#574 is fixed.

See gh-28797

Author: sdeleuze

gradle/spring-module.gradle

@@ -117,10 +117,8 @@ tasks.withType(JavaCompile).configureEach {
     options.errorprone {
     	disableAllChecks = true
         option("NullAway:CustomContractAnnotations", "org.springframework.lang.Contract")
-        option("NullAway:AnnotatedPackages", "org.springframework")
-        option("NullAway:UnannotatedSubPackages", "org.springframework.instrument,org.springframework.context.index," +
-				"org.springframework.asm,org.springframework.cglib,org.springframework.objenesis," +
-				"org.springframework.javapoet,org.springframework.aot.nativex.substitution,org.springframework.aot.nativex.feature")
+        // TODO Replace by proper flag when supported, see https://github.com/uber/NullAway/issues/574
+		option("NullAway:AnnotatedPackages", "")
     }
 }
 tasks.compileJava {

spring-context/src/main/java/org/springframework/instrument/classloading/glassfish/package-info.java

@@ -1,7 +1,4 @@
 /**
  * Support for class instrumentation on GlassFish.
  */
-@NullMarked
 package org.springframework.instrument.classloading.glassfish;
-
-import org.jspecify.annotations.NullMarked;

spring-context/src/main/java/org/springframework/instrument/classloading/jboss/package-info.java

@@ -1,7 +1,4 @@
 /**
  * Support for class instrumentation on JBoss AS 6 and 7.
  */
-@NullMarked
 package org.springframework.instrument.classloading.jboss;
-
-import org.jspecify.annotations.NullMarked;

spring-context/src/main/java/org/springframework/instrument/classloading/package-info.java

@@ -2,7 +2,4 @@
  * Support package for load time weaving based on class loaders,
  * as required by JPA providers (but not JPA-specific).
  */
-@NullMarked
 package org.springframework.instrument.classloading;
-
-import org.jspecify.annotations.NullMarked;

spring-context/src/main/java/org/springframework/instrument/classloading/tomcat/package-info.java

@@ -1,7 +1,4 @@
 /**
  * Support for class instrumentation on Tomcat.
  */
-@NullMarked
 package org.springframework.instrument.classloading.tomcat;
-
-import org.jspecify.annotations.NullMarked;

spring-core/src/main/java/org/springframework/aot/nativex/feature/package-info.java

@@ -1,7 +1,4 @@
 /**
  * GraalVM native image features, not part of Spring Framework public API.
  */
-@NullMarked
 package org.springframework.aot.nativex.feature;
-
-import org.jspecify.annotations.NullMarked;

spring-core/src/main/java/org/springframework/aot/nativex/substitution/package-info.java

@@ -1,7 +1,4 @@
 /**
  * GraalVM native image substitutions, not part of Spring Framework public API.
  */
-@NullMarked
 package org.springframework.aot.nativex.substitution;
-
-import org.jspecify.annotations.NullMarked;

src/checkstyle/checkstyle-suppressions.xml

@@ -37,10 +37,12 @@
 	<suppress files="RootBeanDefinition" checks="EqualsHashCode"/>
 
 	<!-- spring-context -->
+	<suppress files="[\\/]src[\\/]main[\\/]java[\\/]org[\\/]springframework[\\/]instrument[\\/]" checks="RegexpSinglelineJava" id="packageLevelNullMarkedAnnotation"/>
 	<suppress files="SpringAtInjectTckTests" checks="IllegalImportCheck" id="bannedJUnit3Imports"/>
 
 	<!-- spring-core -->
 	<suppress files="[\\/]src[\\/]main[\\/]java[\\/]org[\\/]springframework[\\/](asm|cglib|objenesis|javapoet)[\\/]" checks=".*"/>
+	<suppress files="[\\/]src[\\/]main[\\/]java[\\/]org[\\/]springframework[\\/]aot[\\/]nativex[\\/]" checks="RegexpSinglelineJava" id="packageLevelNullMarkedAnnotation"/>
 	<suppress files="[\\/]src[\\/]main[\\/]java[\\/]org[\\/]springframework[\\/]aot[\\/]nativex[\\/]feature[\\/]" checks="RegexpSinglelineJava" id="systemOutErrPrint"/>
 	<suppress files="[\\/]src[\\/]main[\\/]java[\\/]org[\\/]springframework[\\/](core|util)[\\/](SpringProperties|SystemPropertyUtils)" checks="RegexpSinglelineJava" id="systemOutErrPrint"/>
 	<suppress files="[\\/]src[\\/]main[\\/]java[\\/]org[\\/]springframework[\\/]lang[\\/]" checks="IllegalImport" id="bannedImports" message="javax"/>