dfa6c847f8
* GH-3344: Treat kotlin.Unit return as null in MMIH Fixes https://github.com/spring-projects/spring-integration/issues/3344 When function lambda doesn't return anything (e.g. a `void` method call is the last one), Kotlin produces a `kotlin.Unit` instance as a return value which is not null and produced as a reply message payload. * Fix `MessagingMethodInvokerHelper` to treat a `kotlin.Unit` as `null` for reply making Kotlin lambdas working the same way as Java lambdas when we don't return anything from from there **Cherry-pick to `5.3.x`** * * Introduce `ClassUtils.isKotlinUnit(Class)` API; use it in the `MessagingMethodInvokerHelper` instead of `.getName().equals()` * * Fix since on new `isKotlinUnit()` API
Spring Integration 
Code of Conduct
Please see our Code of conduct.
Reporting Security Vulnerabilities
Please see our Security policy.
Checking out and Building
To check out the project and build from the source, do the following:
git clone git://github.com/spring-projects/spring-integration.git
cd spring-integration
./gradlew build
NOTE: While Spring Integration runs with Java SE 6 or higher, a Java 8 compiler is required to build the project.
If you encounter out of memory errors during the build, increase an available heap and permgen for Gradle:
GRADLE_OPTS='-XX:MaxPermSize=1024m -Xmx1024m'
To build and install jars into your local Maven cache:
./gradlew install
To build api Javadoc (results will be in build/api):
./gradlew api
To build reference documentation (results will be in build/reference):
./gradlew reference
To build complete distribution including -dist, -docs, and -schema zip files (results will be in build/distributions)
./gradlew dist
Using Eclipse
To generate Eclipse metadata (.classpath and .project files), do the following:
./gradlew eclipse
Once complete, you may then import the projects into Eclipse as usual:
File -> Import -> Existing projects into workspace
Browse to the 'spring-integration' root directory. All projects should import free of errors.
Using IntelliJ IDEA
To generate IDEA metadata (.iml and .ipr files), do the following:
./gradlew idea
Resources
For more information, please visit the Spring Integration website at: https://projects.spring.io/spring-integration