Create empty array instead to avoid unnecessary memory allocation

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

@@ -126,7 +126,7 @@ public ApplicationContextFactory[] getObject() throws Exception {
 			factory.setApplicationContext(applicationContext);
 			applicationContextFactories.add(factory);
 		}
-		return applicationContextFactories.toArray(new ApplicationContextFactory[applicationContextFactories.size()]);
+		return applicationContextFactories.toArray(new ApplicationContextFactory[0]);
 	}
 
 	/**

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

@@ -579,7 +579,7 @@ public static void main(String[] args) throws Exception {
 			return;
 		}
 
-		String[] parameters = params.toArray(new String[params.size()]);
+		String[] parameters = params.toArray(new String[0]);
 
 		int result = command.start(jobPath, jobIdentifier, parameters, opts);
 		command.exit(result);

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

@@ -172,8 +172,7 @@ public void write(Chunk<? extends T> chunk) throws Exception {
 
 			if (usingNamedParameters) {
 				if (chunk.getItems().get(0) instanceof Map && this.itemSqlParameterSourceProvider == null) {
-					updateCounts = namedParameterJdbcTemplate.batchUpdate(sql,
-							chunk.getItems().toArray(new Map[chunk.size()]));
+					updateCounts = namedParameterJdbcTemplate.batchUpdate(sql, chunk.getItems().toArray(new Map[0]));
 				}
 				else {
 					SqlParameterSource[] batchArgs = new SqlParameterSource[chunk.size()];

spring-batch-infrastructure/src/main/java/org/springframework/batch/infrastructure/item/database/support/DefaultDataFieldMaxValueIncrementerFactory.java

@@ -153,7 +153,7 @@ public String[] getSupportedIncrementerTypes() {
 			types.add(type.name());
 		}
 
-		return types.toArray(new String[types.size()]);
+		return types.toArray(new String[0]);
 	}
 
 }

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

@@ -62,7 +62,7 @@ public ResourcesItemReader() {
 	 * @param resources the resources
 	 */
 	public void setResources(Resource[] resources) {
-		this.resources = Arrays.asList(resources).toArray(new Resource[resources.length]);
+		this.resources = Arrays.asList(resources).toArray(new Resource[0]);
 	}
 
 	/**

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

@@ -92,7 +92,7 @@ public void setMailErrorHandler(MailErrorHandler mailErrorHandler) {
 	@Override
 	public void write(Chunk<? extends SimpleMailMessage> chunk) throws MailException {
 		try {
-			mailSender.send(chunk.getItems().toArray(new SimpleMailMessage[chunk.size()]));
+			mailSender.send(chunk.getItems().toArray(new SimpleMailMessage[0]));
 		}
 		catch (MailSendException e) {
 			Map<Object, Exception> failedMessages = e.getFailedMessages();

spring-batch-infrastructure/src/main/java/org/springframework/batch/infrastructure/item/mail/javamail/MimeMessageItemWriter.java

@@ -99,7 +99,7 @@ public void setMailErrorHandler(MailErrorHandler mailErrorHandler) {
 	@Override
 	public void write(Chunk<? extends MimeMessage> chunk) throws MailException {
 		try {
-			mailSender.send(chunk.getItems().toArray(new MimeMessage[chunk.size()]));
+			mailSender.send(chunk.getItems().toArray(new MimeMessage[0]));
 		}
 		catch (MailSendException e) {
 			Map<Object, Exception> failedMessages = e.getFailedMessages();

spring-batch-infrastructure/src/main/java/org/springframework/batch/infrastructure/repeat/exception/CompositeExceptionHandler.java

@@ -32,7 +32,7 @@ public class CompositeExceptionHandler implements ExceptionHandler {
 	private ExceptionHandler[] handlers = new ExceptionHandler[0];
 
 	public void setHandlers(ExceptionHandler[] handlers) {
-		this.handlers = Arrays.asList(handlers).toArray(new ExceptionHandler[handlers.length]);
+		this.handlers = Arrays.asList(handlers).toArray(new ExceptionHandler[0]);
 	}
 
 	/**

spring-batch-infrastructure/src/main/java/org/springframework/batch/infrastructure/repeat/policy/CompositeCompletionPolicy.java

@@ -43,7 +43,7 @@ public class CompositeCompletionPolicy implements CompletionPolicy {
 	 * {@link #isComplete(RepeatContext)} by consensus.
 	 */
 	public void setPolicies(CompletionPolicy[] policies) {
-		this.policies = Arrays.asList(policies).toArray(new CompletionPolicy[policies.length]);
+		this.policies = Arrays.asList(policies).toArray(new CompletionPolicy[0]);
 	}
 
 	/**
@@ -127,7 +127,7 @@ protected class CompositeBatchContext extends RepeatContextSupport {
 
 		public CompositeBatchContext(RepeatContext context, List<RepeatContext> contexts) {
 			super(context);
-			this.contexts = contexts.toArray(new RepeatContext[contexts.size()]);
+			this.contexts = contexts.toArray(new RepeatContext[0]);
 			this.policies = CompositeCompletionPolicy.this.policies;
 		}