Migrate nullability annotations to JSpecify

Signed-off-by: Stefano Cordio <[email protected]>

Issue #4673

Author: scordio

pom.xml

@@ -148,7 +148,8 @@
 		<maven-assembly-plugin.version>3.7.1</maven-assembly-plugin.version>
 		<maven-jar-plugin.version>3.4.2</maven-jar-plugin.version>
 		<spring-javaformat-maven-plugin.version>0.0.47</spring-javaformat-maven-plugin.version>
-		<error-prone.version>2.41.0</error-prone.version>
+		<error-prone.version>2.42.0</error-prone.version>
+		<nullaway.version>0.12.10</nullaway.version>
 	</properties>
 
 	<build>
@@ -180,6 +181,14 @@
 						<compilerArg>--should-stop=ifError=FLOW</compilerArg>
 						<compilerArg>
 							-Xplugin:ErrorProne
+							<!-- Check JSpecify annotations -->
+							-Xep:NullAway:ERROR
+							-XepOpt:NullAway:OnlyNullMarked
+							<!-- FIXME Remove once https://github.com/uber/NullAway/pull/1295 is released -->
+							-XepOpt:NullAway:CustomContractAnnotations=org.springframework.lang.Contract
+							-XepOpt:NullAway:SuppressionNameAliases=DataFlowIssue
+							<!-- https://github.com/uber/NullAway/issues/162 -->
+							-XepExcludedPaths:.*/src/test/java/.*
 						</compilerArg>
 					</compilerArgs>
 					<annotationProcessorPaths>
@@ -188,6 +197,11 @@
 							<artifactId>error_prone_core</artifactId>
 							<version>${error-prone.version}</version>
 						</path>
+						<path>
+							<groupId>com.uber.nullaway</groupId>
+							<artifactId>nullaway</artifactId>
+							<version>${nullaway.version}</version>
+						</path>
 					</annotationProcessorPaths>
 				</configuration>
 			</plugin>

spring-batch-core/src/main/java/org/springframework/batch/core/SpringBatchVersion.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.batch.core;
 
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Class that exposes the Spring Batch version. Fetches the "Implementation-Version"
@@ -43,8 +43,7 @@ private SpringBatchVersion() {
 	 * {@code "N/A"} if it cannot be determined.
 	 * @see Package#getImplementationVersion()
 	 */
-	@Nullable
-	public static String getVersion() {
+	public static @Nullable String getVersion() {
 		Package pkg = SpringBatchVersion.class.getPackage();
 		if (pkg != null && pkg.getImplementationVersion() != null) {
 			return pkg.getImplementationVersion();

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/annotation/package-info.java

@@ -4,7 +4,7 @@
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
  */
-@NonNullApi
+@NullMarked
 package org.springframework.batch.core.configuration.annotation;
 
-import org.springframework.lang.NonNullApi;
+import org.jspecify.annotations.NullMarked;

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/package-info.java

@@ -4,7 +4,7 @@
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
  */
-@NonNullApi
+@NullMarked
 package org.springframework.batch.core.configuration;
 
-import org.springframework.lang.NonNullApi;
+import org.jspecify.annotations.NullMarked;

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/GroupAwareJob.java

@@ -15,11 +15,12 @@
  */
 package org.springframework.batch.core.configuration.support;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.batch.core.job.Job;
 import org.springframework.batch.core.job.JobExecution;
 import org.springframework.batch.core.job.parameters.JobParametersIncrementer;
 import org.springframework.batch.core.job.parameters.JobParametersValidator;
-import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 
 /**
@@ -87,8 +88,7 @@ public boolean isRestartable() {
 	}
 
 	@Override
-	@Nullable
-	public JobParametersIncrementer getJobParametersIncrementer() {
+	public @Nullable JobParametersIncrementer getJobParametersIncrementer() {
 		return delegate.getJobParametersIncrementer();
 	}
 

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapJobRegistry.java

@@ -23,6 +23,8 @@
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.batch.core.job.Job;
 import org.springframework.batch.core.configuration.DuplicateJobException;
 import org.springframework.batch.core.configuration.JobRegistry;
@@ -31,7 +33,6 @@
 import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
-import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java

@@ -22,6 +22,8 @@
 import java.util.concurrent.ConcurrentMap;
 
 import org.springframework.batch.core.step.Step;
+
+import org.jspecify.annotations.Nullable;
 import org.springframework.batch.core.configuration.DuplicateJobException;
 import org.springframework.batch.core.configuration.StepRegistry;
 import org.springframework.batch.core.launch.NoSuchJobException;
@@ -62,7 +64,7 @@ public void unregisterStepsFromJob(String jobName) {
 	}
 
 	@Override
-	public Step getStep(String jobName, String stepName) throws NoSuchJobException {
+	public @Nullable Step getStep(String jobName, String stepName) throws NoSuchJobException {
 		Assert.notNull(jobName, "The job name cannot be null.");
 		Assert.notNull(stepName, "The step name cannot be null.");
 		if (!map.containsKey(jobName)) {

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/package-info.java

@@ -4,7 +4,7 @@
  * @author Michael Minella
  * @author Mahmoud Ben Hassine
  */
-@NonNullApi
+@NullMarked
 package org.springframework.batch.core.configuration.support;
 
-import org.springframework.lang.NonNullApi;
+import org.jspecify.annotations.NullMarked;

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/xml/ExceptionElementParser.java

@@ -22,11 +22,13 @@
 import org.springframework.beans.factory.support.ManagedMap;
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.util.xml.DomUtils;
+
+import org.jspecify.annotations.Nullable;
 import org.w3c.dom.Element;
 
 public class ExceptionElementParser {
 
-	public ManagedMap<TypedStringValue, Boolean> parse(Element element, ParserContext parserContext,
+	public @Nullable ManagedMap<TypedStringValue, Boolean> parse(Element element, ParserContext parserContext,
 			String exceptionListName) {
 		List<Element> children = DomUtils.getChildElementsByTagName(element, exceptionListName);
 		if (children.size() == 1) {

spring-batch-core/src/main/java/org/springframework/batch/core/configuration/xml/JobParser.java

@@ -30,6 +30,8 @@
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.util.StringUtils;
 import org.springframework.util.xml.DomUtils;
+
+import org.jspecify.annotations.Nullable;
 import org.w3c.dom.Element;
 
 /**
@@ -158,7 +160,7 @@ else if (listenersElements.size() > 1) {
 	 * @param parserContext The {@link ParserContext}.
 	 * @return the {@link BeanMetadataElement} extracted from the element parameter.
 	 */
-	public BeanMetadataElement parseBeanElement(Element element, ParserContext parserContext) {
+	public @Nullable BeanMetadataElement parseBeanElement(Element element, ParserContext parserContext) {
 		String refAttribute = element.getAttribute(REF_ATTR);
 		Element beanElement = DomUtils.getChildElementByTagName(element, BEAN_ELE);
 		Element refElement = DomUtils.getChildElementByTagName(element, REF_ELE);