c6ecd90abe
`IMAPFolder.idle()` by default keeps idle-ing after each response. We don't need that, because we want to fetch the new mails immediately (over the same connection). To make `idle()` not keep on going, we called `folder.isOpen()` which in most cases makes `idle()` stop by calling `noop()` internally (to keep the connection alive) which leads to the current `idle()`-call being canceled. The problem this commits addresses is that the call to `noop()` only happens if there were no calls in the last second. There is a check for that in `com.sun.mail.imap.IMAPFolder.keepConnectionAlive`. So if a new message appears less then a second after idle started, we will miss it. This new way interrupts `idle()` more often than before, e.g. when there is an expunge-message (i.e. a message was deleted), which we don't care about. But the subsequent `receive()` in IdleTask will simply get no messages and then turn around and start idle-ing again. **Cherry-pick to `5.3.x` & `master`** # Conflicts: # spring-integration-mail/src/main/java/org/springframework/integration/mail/ImapMailReceiver.java # spring-integration-mail/src/test/java/org/springframework/integration/mail/ImapMailReceiverTests.java
Spring Integration 
Code of Conduct
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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