Added @nullable annotation to overriding methods.

Resolves BATCH-2839

Author: mikeldpl

spring-batch-core-tests/src/main/java/org/springframework/batch/core/test/timeout/SleepingItemProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 the original author or authors.
+ * Copyright 2014-2019 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.
@@ -16,11 +16,13 @@
 package org.springframework.batch.core.test.timeout;
 
 import org.springframework.batch.item.ItemProcessor;
+import org.springframework.lang.Nullable;
 
 public class SleepingItemProcessor<I> implements ItemProcessor<I, I> {
 
 	private long millisToSleep;
 
+	@Nullable
 	@Override
 	public I process(I item) throws Exception {
 		Thread.sleep(millisToSleep);

spring-batch-core-tests/src/main/java/org/springframework/batch/core/test/timeout/SleepingTasklet.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 the original author or authors.
+ * Copyright 2014-2019 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.
@@ -19,11 +19,13 @@
 import org.springframework.batch.core.scope.context.ChunkContext;
 import org.springframework.batch.core.step.tasklet.Tasklet;
 import org.springframework.batch.repeat.RepeatStatus;
+import org.springframework.lang.Nullable;
 
 public class SleepingTasklet implements Tasklet {
 
 	private long millisToSleep;
 
+	@Nullable
 	@Override
 	public RepeatStatus execute(StepContribution contribution,
 			ChunkContext chunkContext) throws Exception {

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/concurrent/ConcurrentTransactionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2019 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.
@@ -53,6 +53,7 @@
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseConfigurer;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseFactory;
 import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;
+import org.springframework.lang.Nullable;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@@ -154,13 +155,15 @@ public Flow flow() {
 			return new FlowBuilder<Flow>("flow")
 					.start(stepBuilderFactory.get("flow.step1")
 								.tasklet(new Tasklet() {
+									@Nullable
 									@Override
 									public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
 										return RepeatStatus.FINISHED;
 									}
 								}).build()
 					).next(stepBuilderFactory.get("flow.step2")
 								.tasklet(new Tasklet() {
+									@Nullable
 									@Override
 									public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
 										return RepeatStatus.FINISHED;
@@ -173,6 +176,7 @@ public RepeatStatus execute(StepContribution contribution, ChunkContext chunkCon
 		public Step firstStep() {
 			return stepBuilderFactory.get("firstStep")
 					.tasklet(new Tasklet() {
+						@Nullable
 						@Override
 						public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
 							System.out.println(">> Beginning concurrent job test");
@@ -185,6 +189,7 @@ public RepeatStatus execute(StepContribution contribution, ChunkContext chunkCon
 		public Step lastStep() {
 			return stepBuilderFactory.get("lastStep")
 					.tasklet(new Tasklet() {
+						@Nullable
 						@Override
 						public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
 							System.out.println(">> Ending concurrent job test");

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/ldif/MyMapper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2005-2014 the original author or authors.
+ * Copyright 2005-2019 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.
@@ -16,6 +16,7 @@
 package org.springframework.batch.core.test.ldif;
 
 import org.springframework.batch.item.ldif.RecordMapper;
+import org.springframework.lang.Nullable;
 import org.springframework.ldap.core.LdapAttributes;
 
 /**
@@ -28,8 +29,9 @@
  */
 public class MyMapper implements RecordMapper<LdapAttributes> {
 
+	@Nullable
 	public LdapAttributes mapRecord(LdapAttributes attributes) {
 		return attributes;
 	}
 
-}
+}

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/ldif/builder/MappingLdifReaderBuilderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 the original author or authors.
+ * Copyright 2017-2019 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.
@@ -29,6 +29,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.lang.Nullable;
 import org.springframework.ldap.core.LdapAttributes;
 import org.springframework.test.context.junit4.SpringRunner;
 
@@ -210,6 +211,7 @@ public void handleRecord(LdapAttributes attributes) {
 	}
 
 	public class TestMapper implements RecordMapper<LdapAttributes> {
+		@Nullable
 		@Override
 		public LdapAttributes mapRecord(LdapAttributes attributes) {
 			return attributes;

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/repository/JobSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2019 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.
@@ -27,6 +27,7 @@
 import org.springframework.batch.core.UnexpectedJobExecutionException;
 import org.springframework.batch.core.job.DefaultJobParametersValidator;
 import org.springframework.beans.factory.BeanNameAware;
+import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 
 /**
@@ -149,6 +150,7 @@ public boolean isRestartable() {
 	/* (non-Javadoc)
 	 * @see org.springframework.batch.core.Job#getJobParametersIncrementer()
 	 */
+	@Nullable
 	@Override
 	public JobParametersIncrementer getJobParametersIncrementer() {
 		return null;

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/step/FaultTolerantStepFactoryBeanIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2014 the original author or authors.
+ * Copyright 2010-2019 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.
@@ -48,6 +48,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
+import org.springframework.lang.Nullable;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@@ -189,6 +190,7 @@ public void clear() {
 			counter = -1;
 		}
 
+		@Nullable
 		@Override
 		public synchronized String read() throws Exception, UnexpectedInputException, ParseException {
 			counter++;
@@ -273,6 +275,7 @@ public void clear() {
 			jdbcTemplate.update("DELETE FROM ERROR_LOG where STEP_NAME='processed'");
 		}
 
+		@Nullable
 		@Override
 		public String process(String item) throws Exception {
 			processed.add(item);

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/step/FaultTolerantStepFactoryBeanRollbackIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2014 the original author or authors.
+ * Copyright 2010-2019 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.
@@ -48,6 +48,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
+import org.springframework.lang.Nullable;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@@ -210,6 +211,7 @@ public void clear() {
 			counter = -1;
 		}
 
+		@Nullable
 		@Override
 		public synchronized String read() throws Exception, UnexpectedInputException, ParseException {
 			counter++;
@@ -305,6 +307,7 @@ public void clear() {
 			jdbcTemplate.update("DELETE FROM ERROR_LOG where STEP_NAME='processed'");
 		}
 
+		@Nullable
 		@Override
 		public String process(String item) throws Exception {
 			processed.add(item);

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/step/FaultTolerantStepIntegrationTests.java

@@ -24,6 +24,7 @@
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.item.support.ListItemReader;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.lang.Nullable;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.transaction.PlatformTransactionManager;
@@ -152,6 +153,7 @@ public void testExceptionInProcessDuringChunkScan() throws Exception {
 		ItemProcessor<Integer, Integer> itemProcessor = new ItemProcessor<Integer, Integer>() {
 			private int cpt;
 
+			@Nullable
 			@Override
 			public Integer process(Integer item) throws Exception {
 				cpt++;

spring-batch-core-tests/src/test/java/org/springframework/batch/core/test/step/MapRepositoryFaultTolerantStepFactoryBeanRollbackTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2014 the original author or authors.
+ * Copyright 2010-2019 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.
@@ -41,6 +41,7 @@
 import org.springframework.batch.item.ItemReader;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.support.transaction.ResourcelessTransactionManager;
+import org.springframework.lang.Nullable;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.util.Assert;
@@ -176,6 +177,7 @@ public void clear() {
 			counter = -1;
 		}
 
+		@Nullable
 		@Override
 		public synchronized String read() throws Exception {
 			counter++;
@@ -236,6 +238,7 @@ public void clear() {
 			processed.clear();
 		}
 
+		@Nullable
 		@Override
 		public String process(String item) throws Exception {
 			processed.add(item);