This section shows the major highlights of Spring Batch 5. For more details, please refer to the migration guide.
What’s New in Spring Batch 5.0
Spring Batch 5.0 has the following major themes:
-
Java 17 Requirement
-
Major dependencies upgrade
-
Batch infrastructure configuration updates
-
Batch testing configuration updates
-
Job parameters handling updates
-
Execution context serialization updates
-
SystemCommandTasklet updates
-
New features
-
Pruning
Java 17 Requirement
Spring Batch follows Spring Framework’s baselines for both Java version and third party dependencies. With Spring Batch 5, the Spring Framework version is being upgraded to Spring Framework 6, which requires Java 17. As a result, the Java version requirement for Spring Batch is also increasing to Java 17.
Major dependencies upgrade
To continue the integration with supported versions of the third party libraries that Spring Batch uses, Spring Batch 5 is updating the dependencies across the board to the following versions:
-
Spring Framework 6
-
Spring Integration 6
-
Spring Data 3
-
Spring AMQP 3
-
Spring for Apache Kafka 3
-
Micrometer 1.10
This release also marks the migration to:
-
Jakarta EE 9
-
Hibernate 6
Batch Infrastructure Configuration Updates
Spring Batch 5 includes the following infrastructure configuration updates:
Data Source and Transaction manager Requirement Updates
Historically, Spring Batch provided a map-based job repository and job explorer implementations to work with an in-memory job repository. These implementations were deprecated in version 4 and completely removed in version 5. The recommended replacement is to use the JDBC-based implementations with an embedded database, such as H2, HSQL, and others.
In this release, the @EnableBatchProcessing
annotation configures a JDBC-based JobRepository
, which requires a
DataSource
and PlatformTransactionManager
beans to be defined in the application context. The DataSource
bean
could refer to an embedded database to work with an in-memory job repository.
Transaction Manager Bean Exposure
Until version 4.3, the @EnableBatchProcessing
annotation exposed a transaction manager bean in the application
context. While this was convenient in many cases, the unconditional exposure of a transaction manager could
interfere with a user-defined transaction manager. In this release, @EnableBatchProcessing
no longer exposes a
transaction manager bean in the application context.
New annotation attributes in EnableBatchProcessing
In this release, the @EnableBatchProcessing
annotation provides new attributes to specify which
components and parameters should be used to configure the Batch infrastructure beans. For example,
it is now possible to specify which data source and transaction manager Spring Batch should configure
in the job repository as follows:
@Configuration
@EnableBatchProcessing(dataSourceRef = "batchDataSource", transactionManagerRef = "batchTransactionManager")
public class MyJobConfiguration {
@Bean
public Job job(JobRepository jobRepository) {
return new JobBuilder("myJob", jobRepository)
//define job flow as needed
.build();
}
}
In this example, batchDataSource
and batchTransactionManager
refer to beans in the application context,
and which will be used to configure the job repository and job explorer. There is no need to define a
custom BatchConfigurer
anymore, which was removed in this release.
New configuration class for infrastructure beans
In this release, a new configuration class named DefaultBatchConfiguration
can be used as an alternative to
using @EnableBatchProcessing
for the configuration of infrastructure beans. This class provides infrastructure
beans with default configuration which can be customized as needed. The following snippet shows a typical usage
of this class:
@Configuration
class MyJobConfiguration extends DefaultBatchConfiguration {
@Bean
public Job job(JobRepository jobRepository) {
return new JobBuilder("myJob", jobRepository)
//define job flow as needed
.build();
}
}
In this example, the JobRepository
bean injected in the Job
bean definition is defined in the DefaultBatchConfiguration
class. Custom parameters can be specified by overriding the corresponding getter. For example, the following example shows
how to override the default character encoding used in the job repository and job explorer:
@Configuration
class MyJobConfiguration extends DefaultBatchConfiguration {
@Bean
public Job job(JobRepository jobRepository) {
return new JobBuilder("job", jobRepository)
// define job flow as needed
.build();
}
@Override
protected Charset getCharset() {
return StandardCharsets.ISO_8859_1;
}
}
Job parameters handling updates
Support for any type as a job parameter
This version adds support to use any type as a job parameter, and not only the 4 pre-defined
types (long, double, string, date) as in v4. This change has an impact on how job parameters
are persisted in the database (There are no more 4 distinct columns for each predefined type).
Please check Column change in BATCH_JOB_EXECUTION_PARAMS
for DDL changes. The fully qualified name of the type of the parameter is now persisted as a String
,
as well as the parameter value. String literals are converted to the parameter type with the standard
Spring conversion service. The standard conversion service can be enriched with any required converter
to convert user specific types to and from String literals.
Default job parameter conversion
The default notation of job parameters in v4 was specified as follows:
[+|-]parameterName(parameterType)=value
where parameterType
is one of [string,long,double,date]
. This notation is limited, constraining,
does not play well with environment variables and is not friendly with Spring Boot.
In v5, there are two way to specify job parameters:
Default notation
The default notation is now specified as follows:
parameterName=parameterValue,parameterType,identificationFlag
where parameterType
is the fully qualified name of the type of the parameter. Spring Batch provides
the DefaultJobParametersConverter
to support this notation.
Extended notation
While the default notation is well suited for the majority of use cases, it might not be convenient when the value contains a comma for example. In this case, the extended notation can be used, which is inspired by Spring Boot’s Json Application Properties and is specified as follows:
parameterName='{"value": "parameterValue", "type":"parameterType", "identifying": "booleanValue"}'
where parameterType
is the fully qualified name of the type of the parameter. Spring Batch provides the
JsonJobParametersConverter
to support this notation.
Execution context serialization updates
Starting from v5, the DefaultExecutionContextSerializer
was updated to serialize/deserialize the context to/from Base64.
Moreover, the default ExecutionContextSerializer
configured by @EnableBatchProcessing
or DefaultBatchConfiguration
was changed from JacksonExecutionContextStringSerializer
to DefaultExecutionContextSerializer
. The dependency to
Jackson was made optional. In order to use the JacksonExecutionContextStringSerializer
, jackson-core
should be added
to the classpath.
SystemCommandTasklet updates
The SystemCommandTasklet
has been revisited in this release and was changed as follows:
-
A new strategy interface named
CommandRunner
was introduced in order to decouple the command execution from the tasklet execution. The default implementation is theJvmCommandRunner
which uses thejava.lang.Runtime#exec
API to run system commands. This interface can be implemented to use any other API to run system commands. -
The method that runs the command now accepts an array of `String`s representing the command and its arguments. There is no need anymore to tokenize the command or do any pre-processing. This change makes the API more intuitive, and less prone to errors.
Batch Testing Configuration Updates
Spring Batch 5 includes the following testing configuration updates:
Removal of autowiring from test utilities
Up to version 4.3, the JobLauncherTestUtils
and JobRepositoryTestUtils
used
to autowire the job under test as well as the test datasource to facilitate the
testing infrastructure setup. While this was convenient for most use cases, it
turned out to cause several issues for test contexts where multiple jobs or
multiple data sources are defined.
In this release, we introduced a few changes to remove the autowiring of such
dependencies in order to avoid any issues while importing those utilities either
manually or through the @SpringBatchTest
annotation.
Transaction support in JobExplorer and JobOperator
This release introduces transaction support in the JobExplorer
created through
the JobExplorerFactoryBean
. It is now possible to specify which transaction manager
to use to drive the ready-only transactions when querying the Batch meta-data as well as
customizing the transaction attributes.
The same transaction support was added to the JobOperator
through a new factory bean
named JobOperatorFactoryBean
.
Automatic registration of a JobOperator with EnableBatchProcessing
As of version 4, the EnableBatchProcessing
annotation provided all the basic infrastructure
beans that are required to launch Spring Batch jobs. However, it did not register a job
operator bean, which is the main entry point to stop, restart and abandon job executions.
While these utilities are not used as often as launching jobs, adding a job operator automatically in the application context can be useful to avoid a manual configuration of such a bean by end users.
Improved Java records support
The support for Java records as items in a chunk-oriented step has initially been introduced in v4.3,
but that support was limited due to the fact that v4 has Java 8 as a baseline. The initial support was
based on reflection tricks to create Java records and populate them with data, without having access to the
java.lang.Record
API that was finalised in Java 16.
Now that v5 has Java 17 as a baseline, we have improved records support in Spring Batch by leveraging the
Record
API in different parts of the framework. For example, the FlatFileItemReaderBuilder
is now able
to detect if the item type is a record or a regular class and configure the corresponding FieldSetMapper
implementation accordingly (ie RecordFieldSetMapper
for records and BeanWrapperFieldSetMapper
for regular
classes). The goal here is to make the configuration of the required FieldSetMapper
type transparent to the user.
Batch tracing with Micrometer
With the upgrade to Micrometer 1.10, you can now get Batch tracing in addition to Batch metrics. Spring Batch will create a span for each job and a span for each step within a job. This tracing meta-data can be collected and viewed on a dashboard like Zipkin for example.
Moreover, this release introduces new metrics like the currently active step, as well as the job launch count
through the provided JobLauncher
.
Java 8 features updates
We took the opportunity of this major release to improve the code base with features from Java 8+, for example:
-
Use default methods in interfaces and deprecate "support" classes (see issue 3924)
-
Add
@FunctionalInterface
where appropriate in public APIs (see issue 4107) -
Add support to use types from the Date and Time APIs as job parameters. (see issue 1035$$)
Support for SAP HANA a job repository
This release introduces the support of SAP HANA as an additional supported database for the job repository.
Full support for MariaDB as a separate product
Up until v4.3, Spring Batch provided support for MariaDB by considering it as MySQL. In this release, MariaDB
is treated as an independent product with its own DDL script and DataFieldMaxValueIncrementer
.
New Maven Bill Of Materials for Spring Batch modules
This feature has been requested several times and is finally shipped in v5. It is now possible to use the newly added Maven BOM to import Spring Batch modules with a consistent version number.
UTF-8 by default
Several issues related to characters encoding have been reported over the years in different areas of the framework, like inconsistent default encoding between file-based item readers and writers, serialization/deserialization issues when dealing with multi-byte characters in the execution context, etc.
In the same spirit as JEP 400 and following the UTF-8 manifesto, this release updates the default encoding to UTF-8 in all areas of the framework and ensures this default is configurable as needed.
Full GraalVM native support
The effort towards providing support to compile Spring Batch applications as native executables using the GraalVM native-image compiler has started in v4.2 and was shipped as experimental in v4.3.
In this release, the native support has been improved significantly by providing the necessary runtime hints to natively compile Spring Batch applications with GraalVM and is now considered out of beta.
Execution context Meta-data improvement
In addition to what Spring Batch already persists in the execution context with regard to runtime information (like the step type, restart flag, etc), this release adds an important detail in the execution context which is the Spring Batch version that was used to serialize the context.
While this seems a detail, it has a huge added value when debugging upgrade issue with regard to execution context serialization and deserialization.
Improved documentation
In this release, the documentation was updated to use the Spring Asciidoctor Backend. This backend ensures that all projects from the portfolio follow the same documentation style. For consistency with other projects, the reference documentation of Spring Batch was updated to use this backend in this release.
Pruning
Spring Batch 5 removes a number of items that are no longer needed, including:
API deprecation and removal
In this major release, all APIs that were deprecated in previous versions have been removed. Moreover, some APIs have been deprecated in v5.0 and are scheduled for removal in v5.2. Finally, some APIs have been moved or removed without deprecation for practical reasons.
Please refer to the migration guide for more details about these changes.
SQLFire Support Removal
SqlFire has been announced to be EOL as of November 1st, 2014. The support of SQLFire as a job repository was deprecated in version v4.3 and removed in version v5.0.
GemFire support removal
Based on the [decision to discontinue](https://github.com/spring-projects/spring-data-geode#notice ) the support of Spring Data for Apache Geode, the support for Geode in Spring Batch was removed. The code was moved to the [spring-batch-extensions](https://github.com/spring-projects/spring-batch-extensions) repository as a community-driven effort.