Add JSR-305 annotations to public APIs

(Partially) Resolves BATCH-2688

spring-batch-core/src/main/java/org/springframework/batch/core/scope/context/StepContextRepeatCallback.java

@@ -25,7 +25,6 @@ import org.springframework.batch.core.StepExecution;
 import org.springframework.batch.repeat.RepeatCallback;
 import org.springframework.batch.repeat.RepeatContext;
 import org.springframework.batch.repeat.RepeatStatus;
-import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -62,7 +61,6 @@ public abstract class StepContextRepeatCallback implements RepeatCallback {
 	 * @see RepeatCallback#doInIteration(RepeatContext)
 	 */
 	@Override
-	@Nullable
 	public RepeatStatus doInIteration(RepeatContext context) throws Exception {
 
 		// The StepContext has to be the same for all chunks,
@@ -109,7 +107,6 @@ public abstract class StepContextRepeatCallback implements RepeatCallback {
 	 * @throws Exception implementations can throw an exception if anything goes
 	 * wrong
 	 */
-	@Nullable
 	public abstract RepeatStatus doInChunkContext(RepeatContext context, ChunkContext chunkContext) throws Exception;
 
 }

spring-batch-core/src/main/java/org/springframework/batch/core/step/tasklet/TaskletStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2014 the original author or authors.
+ * Copyright 2006-2018 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.
@@ -72,6 +72,7 @@ import java.util.concurrent.Semaphore;
  * @author Robert Kasanicky
  * @author Michael Minella
  * @author Will Schipp
+ * @author Mahmoud Ben Hassine
  */
 @SuppressWarnings("serial")
 public class TaskletStep extends AbstractStep {
@@ -283,7 +284,7 @@ public class TaskletStep extends AbstractStep {
 				// caller
 				interruptionPolicy.checkInterrupted(stepExecution);
 
-				return result;
+				return result == null ? RepeatStatus.FINISHED : result;
 			}
 
 		});

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/ExecutionContext.java

@@ -156,7 +156,6 @@ public class ExecutionContext implements Serializable {
 	 * @param key The key to get a value for
 	 * @return The <code>String</code> value
 	 */
-	@Nullable
 	public String getString(String key) {
 
 		return (String) readAndValidate(key, String.class);
@@ -171,7 +170,6 @@ public class ExecutionContext implements Serializable {
 	 * @return The <code>String</code> value if key is represented, specified
 	 * default otherwise
 	 */
-	@Nullable
 	public String getString(String key, String defaultString) {
 		if (!containsKey(key)) {
 			return defaultString;

spring-batch-test/src/main/java/org/springframework/batch/test/ExecutionContextTestUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2009 the original author or authors.
+ * Copyright 2006-2018 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.
@@ -22,22 +22,26 @@ import java.util.List;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.StepExecution;
 import org.springframework.batch.item.ExecutionContext;
+import org.springframework.lang.Nullable;
 
 /**
  * Convenience class for accessing {@link ExecutionContext} values from job and
  * step executions.
  * 
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.1.4
  * 
  */
 public class ExecutionContextTestUtils {
 
 	@SuppressWarnings("unchecked")
+	@Nullable
 	public static <T> T getValueFromJob(JobExecution jobExecution, String key) {
 		return (T) jobExecution.getExecutionContext().get(key);
 	}
 
+	@Nullable
 	public static <T> T getValueFromStepInJob(JobExecution jobExecution, String stepName, String key) {
 		StepExecution stepExecution = null;
 		List<String> stepNames = new ArrayList<String>();
@@ -58,6 +62,7 @@ public class ExecutionContextTestUtils {
 	}
 
 	@SuppressWarnings("unchecked")
+	@Nullable
 	public static <T> T getValueFromStep(StepExecution stepExecution, String key) {
 		return (T) stepExecution.getExecutionContext().get(key);
 	}

spring-batch-test/src/main/java/org/springframework/batch/test/JobLauncherTestUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2018 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.
@@ -35,6 +35,7 @@ import org.springframework.batch.core.step.StepLocator;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.ApplicationContext;
+import org.springframework.lang.Nullable;
 
 /**
  * <p>
@@ -62,6 +63,7 @@ import org.springframework.context.ApplicationContext;
  * @author Lucas Ward
  * @author Dan Garrette
  * @author Dave Syer
+ * @author Mahmoud Ben Hassine
  * @since 2.1
  */
 public class JobLauncherTestUtils {
@@ -223,7 +225,7 @@ public class JobLauncherTestUtils {
 	 * loaded into the Job ExecutionContext prior to launching the step.
 	 * @return JobExecution
 	 */
-	public JobExecution launchStep(String stepName, JobParameters jobParameters, ExecutionContext jobExecutionContext) {
+	public JobExecution launchStep(String stepName, JobParameters jobParameters, @Nullable ExecutionContext jobExecutionContext) {
 		if (!(job instanceof StepLocator)) {
 			throw new UnsupportedOperationException("Cannot locate step from a Job that is not a StepLocator: job="
 					+ job.getName() + " does not implement StepLocator");

spring-batch-test/src/main/java/org/springframework/batch/test/JobRepositoryTestUtils.java

@@ -41,6 +41,7 @@ import org.springframework.dao.DataAccessException;
 import org.springframework.jdbc.core.JdbcOperations;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -61,7 +62,7 @@ public class JobRepositoryTestUtils extends AbstractJdbcBatchMetadataDao impleme
 		Long count = 0L;
 
 		@Override
-		public JobParameters getNext(JobParameters parameters) {
+		public JobParameters getNext(@Nullable JobParameters parameters) {
 			return new JobParameters(Collections.singletonMap("count", new JobParameter(count++)));
 		}
 

spring-batch-test/src/main/java/org/springframework/batch/test/JsrTestUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -25,11 +25,14 @@ import java.util.Date;
 import java.util.Properties;
 import java.util.concurrent.TimeoutException;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Provides testing utilities to execute JSR-352 jobs and block until they are complete (since all JSR-352 based jobs
  * are executed asynchronously).
  *
  * @author Michael Minella
+ * @author Mahmoud Ben Hassine
  * @since 3.0
  */
 public class JsrTestUtils {
@@ -110,6 +113,7 @@ public class JsrTestUtils {
 		return execution;
 	}
 
+	@Nullable
 	public static Metric getMetric(StepExecution stepExecution, Metric.MetricType type) {
 		Metric[] metrics = stepExecution.getMetrics();
 

spring-batch-test/src/main/java/org/springframework/batch/test/StepRunner.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2018 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.
@@ -40,6 +40,7 @@ import org.springframework.batch.core.repository.JobInstanceAlreadyCompleteExcep
 import org.springframework.batch.core.repository.JobRepository;
 import org.springframework.batch.core.repository.JobRestartException;
 import org.springframework.batch.item.ExecutionContext;
+import org.springframework.lang.Nullable;
 
 /**
  * Utility class for executing steps outside of a {@link Job}. This is useful in
@@ -61,6 +62,7 @@ import org.springframework.batch.item.ExecutionContext;
  *
  * @author Dan Garrette
  * @author Lucas Ward
+ * @author Mahmoud Ben Hassine
  * @since 2.0
  * @see SimpleJob
  */
@@ -100,7 +102,7 @@ public class StepRunner {
 	 * loaded into the Job ExecutionContext prior to launching the step.
 	 * @return JobExecution
 	 */
-	public JobExecution launchStep(Step step, ExecutionContext jobExecutionContext) {
+	public JobExecution launchStep(Step step, @Nullable ExecutionContext jobExecutionContext) {
 		return this.launchStep(step, this.makeUniqueJobParameters(), jobExecutionContext);
 	}
 
@@ -126,7 +128,7 @@ public class StepRunner {
 	 * loaded into the Job ExecutionContext prior to launching the step.
 	 * @return JobExecution
 	 */
-	public JobExecution launchStep(Step step, JobParameters jobParameters, final ExecutionContext jobExecutionContext) {
+	public JobExecution launchStep(Step step, JobParameters jobParameters, @Nullable final ExecutionContext jobExecutionContext) {
 		//
 		// Create a fake job
 		//

spring-batch-test/src/main/java/org/springframework/batch/test/context/package-info.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2018 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.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * APIs for the configuration of Spring Batch test support.
+ *
+ * @author Mahmoud Ben Hassine
+ */
+@NonNullApi
+package org.springframework.batch.test.context;
+
+import org.springframework.lang.NonNullApi;

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

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2018 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.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Utility classes for batch job/step testing.
+ *
+ * @author Mahmoud Ben Hassine
+ */
+@NonNullApi
+package org.springframework.batch.test;
+
+import org.springframework.lang.NonNullApi;