Spring Integration Java DSL problems at startup with Http Outbound Gateway - spring

Question

I'm new to Spring Integration and am trying to develop an application which simply (1) polls a folder for new files with extension .dat containing data in csv format (2) initialize for each line a domain POJO object of class RecordDTO and finally (3) sends this object as payload to a REST service with a POST.
For this I'm trying to use Java DSL for Spring Integration.
The problem I'm getting is the following VerifyError / HttpRequestExecutingMessageHandler overrides final method onInit. exception.
2016-07-22 10:01:38.965 ERROR 4460 --- [ main] o.s.boot.SpringApplication : Application startup failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'upcase' defined in eu.softeco.examples.SpringBootIntegrationTestApplication: Initialization of bean failed; nest
ed exception is java.lang.VerifyError: class org.springframework.integration.http.outbound.HttpRequestExecutingMessageHandler overrides final method onInit.()V
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.1.RELEASE.jar:4.3.1.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.1.RELEASE.jar:4.3.1.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.1.RELEASE.jar:4.3.1.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.1.RELEASE.jar:4.3.1.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.1.RELEASE.jar:4.3.1.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.1.RELEASE.jar:4.3.1.RELEASE]
...
Caused by: java.lang.VerifyError: class org.springframework.integration.http.outbound.HttpRequestExecutingMessageHandler overrides final method onInit.()V
at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_45]
at java.lang.ClassLoader.defineClass(ClassLoader.java:760) ~[na:1.8.0_45]
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[na:1.8.0_45]
...
Below are relevant details concerning my code and maven configuration. Please not that
1) the problem is at startup, before any data is put in the input folder
2) if I replace the final Http outboundGateway step with the simple (commented) System.out.println, everything works fine.
Following are code/config details. This is my main Spring Boot application class with Spring Integration Flow definition:
#SpringBootApplication
#EnableIntegration
#IntegrationComponentScan
public class SpringBootIntegrationTestApplication {
...
public static void main(String[] args) {
SpringApplication.run(SpringBootIntegrationTestApplication.class, args);
}
/**
* Inbound FileReadingMessageSource
*/
#Bean
#InboundChannelAdapter(channel = "upcase.input", poller = #Poller(fixedDelay = "4000"))
public MessageSource<File> fileReadingMessageSource() {
FileReadingMessageSource source = new FileReadingMessageSource();
source.setDirectory(new File(INBOUND_PATH));
source.setFilter(new SimplePatternFileListFilter("*.dat"));
return source;
}
/**
* Spring Integration Java DSL Flow
*/
#Bean
public IntegrationFlow upcase() {
FileToStringTransformer fileToStringTranformer = Transformers.fileToString();
fileToStringTranformer.setDeleteFiles(true);
return flow -> flow
// get string contents from fie
.transform(fileToStringTranformer)
// split into individual lines
.split( s -> s.applySequence(true).get().getT2().setDelimiters("\n"))
// cleanup lines from trailing returns
.transform( (String s) -> s.replace("\n", "").replace("\r", "") )
// convert csv string to RecordDTO object
.transform("#recordFromCsvTransformer.transform(payload)")
// print on System.out
// .handle(m -> System.out.println(m.getPayload()))
// send to
.handle(Http.outboundGateway("http://localhost:8080/records")
.httpMethod(HttpMethod.POST)
.expectedResponseType(RecordDTO.class));
}
}
Below the RecordFromCsvTransformer class
#Component
public class RecordFromCsvTransformer
{
#Transformer
public RecordDTO transform(String csvline) throws Exception {
RecordDTO record = new RecordDTO();
... parse csv and initialize record's fields...
return record;
}
}
And Finally the relevant parts of pom.xml (dependencies);
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.0.RC1</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
...
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-integration</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.integration</groupId>
<artifactId>spring-integration-file</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.integration</groupId>
<artifactId>spring-integration-http</artifactId>
<version>2.1.0.RELEASE</version>
</dependency>
...
</dependencies>
...
As a side question in general, can someone suggest me some good tutorial / getting started guide to learn Spring Integration with Java Annotation/Java DSL? So far I've only found either introductory guide based on Spring Integration XML configuration or material about Java Annotations/DSL but that already requires prior knowledge of Spring Integration.

Answer 1

<version>2.1.0.RELEASE</version>
That version of Spring Integration is mismatched with the spring-integration-core version brought in transitively by maven.
You need to use the same version of all spring-integration-* files - check which version of spring-integration-file is being pulled in by boot and use the same version.