Fix NullAway findings

Signed-off-by: Stefano Cordio <stefano.cordio@gmail.com>

Author: scordio

pom.xml

@@ -191,6 +191,7 @@
 							<!-- Check JSpecify annotations -->
 							-Xep:NullAway:ERROR
 							-XepOpt:NullAway:OnlyNullMarked
+							-XepOpt:NullAway:CustomContractAnnotations=org.springframework.lang.Contract
 						</compilerArg>
 					</compilerArgs>
 					<annotationProcessorPaths>

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

@@ -222,9 +222,9 @@ private Collection<Job> doLoad(ApplicationContextFactory factory, boolean unregi
 	 * @return all the {@link Step} defined by the given step locator and context
 	 * @see StepLocator
 	 */
-	private Collection<Step> getSteps(final StepLocator stepLocator, final ApplicationContext jobApplicationContext) {
-		final Collection<String> stepNames = stepLocator.getStepNames();
-		final Collection<Step> result = new ArrayList<>();
+	private Collection<Step> getSteps(StepLocator stepLocator, ApplicationContext jobApplicationContext) {
+		Collection<String> stepNames = stepLocator.getStepNames();
+		Collection<Step> result = new ArrayList<>();
 		for (String stepName : stepNames) {
 			result.add(stepLocator.getStep(stepName));
 		}
@@ -234,7 +234,7 @@ private Collection<Step> getSteps(final StepLocator stepLocator, final Applicati
 		// are more Step instances defined. Right now they are registered as being
 		// available in the
 		// context of the job but we have no idea if they are linked to that Job or not.
-		final Map<String, Step> allSteps = jobApplicationContext.getBeansOfType(Step.class);
+		Map<String, Step> allSteps = jobApplicationContext.getBeansOfType(Step.class);
 		for (Map.Entry<String, Step> entry : allSteps.entrySet()) {
 			if (!stepNames.contains(entry.getKey())) {
 				result.add(entry.getValue());

spring-batch-core/src/main/java/org/springframework/batch/core/job/flow/FlowExecutor.java

@@ -51,8 +51,7 @@ public interface FlowExecutor {
 	/**
 	 * @return the latest {@link StepExecution} or null if there is none
 	 */
-	@Nullable
-	StepExecution getStepExecution();
+	@Nullable StepExecution getStepExecution();
 
 	/**
 	 * Chance to clean up resources at the end of a flow (whether it completed

spring-batch-core/src/main/java/org/springframework/batch/core/job/flow/FlowJob.java

@@ -127,7 +127,7 @@ public Collection<String> getStepNames() {
 	 * @see AbstractJob#doExecute(JobExecution)
 	 */
 	@Override
-	protected void doExecute(final JobExecution execution) throws JobExecutionException {
+	protected void doExecute(JobExecution execution) throws JobExecutionException {
 		try {
 			JobFlowExecutor executor = new JobFlowExecutor(getJobRepository(),
 					new SimpleStepHandler(getJobRepository()), execution);

spring-batch-core/src/main/java/org/springframework/batch/core/job/flow/support/state/SplitState.java

@@ -97,13 +97,13 @@ public Collection<Flow> getFlows() {
 	 * @see State#handle(FlowExecutor)
 	 */
 	@Override
-	public FlowExecutionStatus handle(final FlowExecutor executor) throws Exception {
+	public FlowExecutionStatus handle(FlowExecutor executor) throws Exception {
 
 		// TODO: collect the last StepExecution from the flows as well, so they
 		// can be abandoned if necessary
 		Collection<Future<FlowExecution>> tasks = new ArrayList<>();
 
-		for (final Flow flow : flows) {
+		for (Flow flow : flows) {
 
 			final FutureTask<FlowExecution> task = new FutureTask<>(() -> flow.start(executor));
 

spring-batch-core/src/main/java/org/springframework/batch/core/launch/support/TaskExecutorJobLauncher.java

@@ -98,9 +98,8 @@ public class TaskExecutorJobLauncher implements JobLauncher, InitializingBean {
 	 * @throws JobParametersInvalidException thrown if jobParameters is invalid.
 	 */
 	@Override
-	public JobExecution run(final Job job, final JobParameters jobParameters)
-			throws JobExecutionAlreadyRunningException, JobRestartException, JobInstanceAlreadyCompleteException,
-			JobParametersInvalidException {
+	public JobExecution run(Job job, final JobParameters jobParameters) throws JobExecutionAlreadyRunningException,
+			JobRestartException, JobInstanceAlreadyCompleteException, JobParametersInvalidException {
 
 		Assert.notNull(job, "The Job must not be null.");
 		Assert.notNull(jobParameters, "The JobParameters must not be null.");

spring-batch-core/src/main/java/org/springframework/batch/core/partition/support/AbstractPartitionHandler.java

@@ -52,7 +52,7 @@ protected abstract Set<StepExecution> doHandle(StepExecution managerStepExecutio
 	 * @see PartitionHandler#handle(StepExecutionSplitter, StepExecution)
 	 */
 	@Override
-	public Collection<StepExecution> handle(final StepExecutionSplitter stepSplitter,
+	public Collection<StepExecution> handle(StepExecutionSplitter stepSplitter,
 			final StepExecution managerStepExecution) throws Exception {
 		final Set<StepExecution> stepExecutions = stepSplitter.split(managerStepExecution, gridSize);
 

spring-batch-core/src/main/java/org/springframework/batch/core/partition/support/TaskExecutorPartitionHandler.java

@@ -93,7 +93,7 @@ protected Set<StepExecution> doHandle(StepExecution managerStepExecution,
 		final Set<Future<StepExecution>> tasks = new HashSet<>(getGridSize());
 		final Set<StepExecution> result = new HashSet<>();
 
-		for (final StepExecution stepExecution : partitionStepExecutions) {
+		for (StepExecution stepExecution : partitionStepExecutions) {
 			final FutureTask<StepExecution> task = createTask(step, stepExecution);
 
 			try {
@@ -127,7 +127,7 @@ protected Set<StepExecution> doHandle(StepExecution managerStepExecution,
 	 * @param stepExecution the given execution
 	 * @return the task executing the given step
 	 */
-	protected FutureTask<StepExecution> createTask(final Step step, final StepExecution stepExecution) {
+	protected FutureTask<StepExecution> createTask(Step step, final StepExecution stepExecution) {
 		return new FutureTask<>(() -> {
 			step.execute(stepExecution);
 			return stepExecution;

spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/ExecutionContextDao.java

@@ -48,36 +48,36 @@ public interface ExecutionContextDao {
 	 * entry for the context should not exist yet.
 	 * @param jobExecution {@link JobExecution} instance that contains the context.
 	 */
-	void saveExecutionContext(final JobExecution jobExecution);
+	void saveExecutionContext(JobExecution jobExecution);
 
 	/**
 	 * Persist the execution context associated with the given stepExecution, persistent
 	 * entry for the context should not exist yet.
 	 * @param stepExecution {@link StepExecution} instance that contains the context.
 	 */
-	void saveExecutionContext(final StepExecution stepExecution);
+	void saveExecutionContext(StepExecution stepExecution);
 
 	/**
 	 * Persist the execution context associated with each stepExecution in a given
 	 * collection, persistent entry for the context should not exist yet.
 	 * @param stepExecutions a collection of {@link StepExecution}s that contain the
 	 * contexts.
 	 */
-	void saveExecutionContexts(final Collection<StepExecution> stepExecutions);
+	void saveExecutionContexts(Collection<StepExecution> stepExecutions);
 
 	/**
 	 * Persist the updates of execution context associated with the given jobExecution.
 	 * Persistent entry should already exist for this context.
 	 * @param jobExecution {@link JobExecution} instance that contains the context.
 	 */
-	void updateExecutionContext(final JobExecution jobExecution);
+	void updateExecutionContext(JobExecution jobExecution);
 
 	/**
 	 * Persist the updates of execution context associated with the given stepExecution.
 	 * Persistent entry should already exist for this context.
 	 * @param stepExecution {@link StepExecution} instance that contains the context.
 	 */
-	void updateExecutionContext(final StepExecution stepExecution);
+	void updateExecutionContext(StepExecution stepExecution);
 
 	/**
 	 * Delete the execution context of the given {@link JobExecution}.

spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/JobExecutionDao.java

@@ -19,13 +19,9 @@
 import java.util.List;
 import java.util.Set;
 
+import org.jspecify.annotations.Nullable;
 import org.springframework.batch.core.job.JobExecution;
 import org.springframework.batch.core.job.JobInstance;
-import org.springframework.lang.Nullable;
-import org.springframework.batch.core.JobExecution;
-
-import org.jspecify.annotations.Nullable;
-import org.springframework.batch.core.JobInstance;
 
 /**
  * Data Access Object for job executions.
@@ -68,8 +64,7 @@ public interface JobExecutionDao {
 	 * @return the last {@link JobExecution} to execute for this instance or {@code null}
 	 * if no job execution is found for the given job instance.
 	 */
-	@Nullable
-	JobExecution getLastJobExecution(JobInstance jobInstance);
+	@Nullable JobExecution getLastJobExecution(JobInstance jobInstance);
 
 	/**
 	 * @param jobName {@link String} containing the name of the job.
@@ -82,8 +77,7 @@ public interface JobExecutionDao {
 	 * @param executionId {@link Long} containing the id of the execution.
 	 * @return the {@link JobExecution} for given identifier.
 	 */
-	@Nullable
-	JobExecution getJobExecution(Long executionId);
+	@Nullable JobExecution getJobExecution(Long executionId);
 
 	/**
 	 * Because it may be possible that the status of a JobExecution is updated while