Fixes: https://github.com/spring-projects/spring-integration/issues/3249 When the `CachingSessionFactory` is configured with small enough pool and it is very likely that dead lock may happen when `RemoteFileTemplate.send()` is used. The problem happens when we reach the `RemoteFileTemplate.exists()` call which is done from the internal method called from already pulled from cache `Session` * Fix `RemoteFileTemplate` to use a `session.exists()` instead on the provided into the method `Session` * Demonstrate the problem in the `SftpRemoteFileTemplateTests.testNoDeadLockOnSend()` **Cherry-pick to 5.2.x, 5.1.x & 4.3.x** Fix RemoteFileOutboundGWTests for the proper mock
Spring Integration 
Checking out and Building
To check out the project and build from 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 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