Refine contribution #4990

This commit updates nullability checks based on the new
changes introduced in #1870. The main refinements are:

- Add constructors with mandatory properties
- Avoid accepting nullable parameters where appropriate

Some classes have been excluded from nullability checks
util we fully remove the "no-arg constructor + setters +
afterPropertiesSet" approach to creating objects.

Resolves #4673

Author: fmbenhassine

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

@@ -19,6 +19,8 @@
 import java.io.Serializable;
 import java.util.Objects;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.util.ClassUtils;
 
 /**
@@ -35,7 +37,7 @@ public class Entity implements Serializable {
 
 	private final long id;
 
-	private Integer version;
+	private @Nullable Integer version;
 
 	/**
 	 * The constructor for the {@link Entity} where the ID is established.
@@ -55,7 +57,7 @@ public long getId() {
 	/**
 	 * @return the version.
 	 */
-	public Integer getVersion() {
+	public @Nullable Integer getVersion() {
 		return version;
 	}
 

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

@@ -18,6 +18,7 @@
 import io.micrometer.observation.ObservationRegistry;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.batch.core.job.AbstractJob;
 import org.springframework.batch.core.launch.support.TaskExecutorJobOperator;
@@ -39,7 +40,7 @@ public class BatchObservabilityBeanPostProcessor implements BeanFactoryPostProce
 
 	private static final Log LOGGER = LogFactory.getLog(BatchObservabilityBeanPostProcessor.class);
 
-	private ConfigurableListableBeanFactory beanFactory;
+	private @Nullable ConfigurableListableBeanFactory beanFactory;
 
 	@Override
 	public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
@@ -48,6 +49,10 @@ public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
 
 	@Override
 	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+		if (this.beanFactory == null) {
+			LOGGER.warn("BeanFactory is not initialized, skipping observation registry injection");
+			return bean;
+		}
 		try {
 			if (bean instanceof AbstractJob || bean instanceof AbstractStep
 					|| bean instanceof TaskExecutorJobOperator) {

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

@@ -16,6 +16,7 @@
 package org.springframework.batch.core.configuration.support;
 
 import io.micrometer.observation.ObservationRegistry;
+import org.jspecify.annotations.NullUnmarked;
 
 import org.springframework.batch.core.configuration.DuplicateJobException;
 import org.springframework.batch.core.configuration.annotation.BatchObservabilityBeanPostProcessor;
@@ -78,6 +79,7 @@
  */
 @Configuration(proxyBeanMethods = false)
 @Import({ ScopeConfiguration.class, BatchObservabilityBeanPostProcessor.class })
+@NullUnmarked
 public class DefaultBatchConfiguration implements ApplicationContextAware {
 
 	protected ApplicationContext applicationContext;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2023 the original author or authors.
+ * Copyright 2006-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,21 +48,12 @@ public class GroupAwareJob implements Job {
 
 	private final String groupName;
 
-	/**
-	 * Create a new {@link Job} with the delegate and no group name.
-	 * @param delegate a delegate for the features of a regular Job
-	 */
-	public GroupAwareJob(Job delegate) {
-		this(null, delegate);
-	}
-
 	/**
 	 * Create a new {@link Job} with the given group name and delegate.
 	 * @param groupName the group name to prepend (can be {@code null})
 	 * @param delegate a delegate for the features of a regular Job
 	 */
-	public GroupAwareJob(@Nullable String groupName, Job delegate) {
-		super();
+	public GroupAwareJob(String groupName, Job delegate) {
 		this.groupName = groupName;
 		this.delegate = delegate;
 	}
@@ -79,7 +70,7 @@ public void execute(JobExecution execution) {
 	 */
 	@Override
 	public String getName() {
-		return groupName == null ? delegate.getName() : groupName + SEPARATOR + delegate.getName();
+		return groupName + SEPARATOR + delegate.getName();
 	}
 
 	@Override

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

@@ -23,7 +23,7 @@
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.jspecify.annotations.Nullable;
+import org.jspecify.annotations.NullUnmarked;
 
 import org.springframework.batch.core.job.Job;
 import org.springframework.batch.core.configuration.DuplicateJobException;
@@ -44,6 +44,7 @@
  * @author Robert Fischer
  * @author Mahmoud Ben Hassine
  */
+@NullUnmarked // FIXME how to fix nullability checks for the applicationContext field?
 public class MapJobRegistry implements JobRegistry, SmartInitializingSingleton, ApplicationContextAware {
 
 	protected final Log logger = LogFactory.getLog(getClass());
@@ -84,7 +85,7 @@ public void unregister(String name) {
 	}
 
 	@Override
-	public Job getJob(@Nullable String name) throws NoSuchJobException {
+	public Job getJob(String name) throws NoSuchJobException {
 		Job job = this.map.get(name);
 		if (job == null) {
 			throw new NoSuchJobException("No job with the name [" + name + "] was registered");

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,7 +64,7 @@ public void unregisterStepsFromJob(String jobName) {
 	}
 
 	@Override
-	public @Nullable Step getStep(String jobName, String stepName) throws NoSuchJobException {
+	public 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/converter/JsonJobParametersConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2023 the original author or authors.
+ * Copyright 2022-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.batch.core.job.parameters.JobParameter;
 import org.springframework.batch.core.job.parameters.JobParameters;
@@ -91,6 +92,10 @@ protected String encode(JobParameter<?> jobParameter) {
 		Object parameterTypedValue = jobParameter.getValue();
 		boolean parameterIdentifying = jobParameter.isIdentifying();
 		String parameterStringValue = this.conversionService.convert(parameterTypedValue, String.class);
+		if (parameterStringValue == null) {
+			throw new JobParametersConversionException(
+					"Unable to encode job parameter of type " + parameterType + " with value " + parameterTypedValue);
+		}
 		try {
 			return this.objectMapper.writeValueAsString(new JobParameterDefinition(parameterStringValue,
 					parameterType.getName(), Boolean.toString(parameterIdentifying)));
@@ -122,7 +127,7 @@ protected JobParameter decode(String encodedJobParameter) {
 		}
 	}
 
-	public record JobParameterDefinition(String value, String type, String identifying) {
+	public record JobParameterDefinition(String value, @Nullable String type, @Nullable String identifying) {
 	}
 
 }

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

@@ -25,7 +25,7 @@
 import io.micrometer.observation.ObservationRegistry;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.jspecify.annotations.Nullable;
+import org.jspecify.annotations.NullUnmarked;
 
 import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.ExitStatus;
@@ -62,6 +62,7 @@
  * @author Dave Syer
  * @author Mahmoud Ben Hassine
  */
+@NullUnmarked // FIXME to remove once default constructors are removed
 public abstract class AbstractJob implements Job, StepLocator, BeanNameAware, InitializingBean {
 
 	protected static final Log logger = LogFactory.getLog(AbstractJob.class);
@@ -200,7 +201,7 @@ public void setJobParametersIncrementer(JobParametersIncrementer jobParametersIn
 	}
 
 	@Override
-	public @Nullable JobParametersIncrementer getJobParametersIncrementer() {
+	public JobParametersIncrementer getJobParametersIncrementer() {
 		return this.jobParametersIncrementer;
 	}
 

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

@@ -52,7 +52,7 @@ public String generateKey(JobParameters source) {
 		Collections.sort(keys);
 		for (String key : keys) {
 			JobParameter<?> jobParameter = props.get(key);
-			if (jobParameter.isIdentifying()) {
+			if (jobParameter != null && jobParameter.isIdentifying()) {
 				String value = jobParameter.toString();
 				stringBuffer.append(key).append("=").append(value).append(";");
 			}

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

@@ -26,11 +26,14 @@
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 
-import org.springframework.batch.core.*;
+import org.jspecify.annotations.Nullable;
+
+import org.springframework.batch.core.BatchStatus;
+import org.springframework.batch.core.Entity;
+import org.springframework.batch.core.ExitStatus;
 import org.springframework.batch.core.job.parameters.JobParameters;
 import org.springframework.batch.core.step.StepExecution;
 import org.springframework.batch.item.ExecutionContext;
-import org.springframework.lang.Nullable;
 
 /**
  * Batch domain object representing the execution of a job.
@@ -54,11 +57,11 @@ public class JobExecution extends Entity {
 
 	private LocalDateTime createTime = LocalDateTime.now();
 
-	private LocalDateTime startTime = null;
+	private @Nullable LocalDateTime startTime = null;
 
-	private LocalDateTime endTime = null;
+	private @Nullable LocalDateTime endTime = null;
 
-	private LocalDateTime lastUpdated = null;
+	private @Nullable LocalDateTime lastUpdated = null;
 
 	private ExitStatus exitStatus = ExitStatus.UNKNOWN;
 
@@ -92,8 +95,7 @@ public JobParameters getJobParameters() {
 	/**
 	 * @return The current end time.
 	 */
-	@Nullable
-	public LocalDateTime getEndTime() {
+	@Nullable public LocalDateTime getEndTime() {
 		return endTime;
 	}
 
@@ -116,8 +118,7 @@ public void setEndTime(LocalDateTime endTime) {
 	/**
 	 * @return The current start time.
 	 */
-	@Nullable
-	public LocalDateTime getStartTime() {
+	@Nullable public LocalDateTime getStartTime() {
 		return startTime;
 	}
 
@@ -265,8 +266,7 @@ public void addStepExecutions(List<StepExecution> stepExecutions) {
 	 * @return a {@link LocalDateTime} object representing the last time this
 	 * {@code JobExecution} was updated.
 	 */
-	@Nullable
-	public LocalDateTime getLastUpdated() {
+	@Nullable public LocalDateTime getLastUpdated() {
 		return lastUpdated;
 	}