Thread [Connect-Scheduler-Check-Timer] fail to iterate the connectionMap , because other threads will modify the connectionMap at the same time. Fe's connection which is timed out can't be released because of thread [Connect-Scheduler-Check-Timer] not working.
# fe-common This module is used to store some common classes of other modules. # spark-dpp This module is Spark DPP program, used for Spark Load function. Depends: fe-common # fe-core This module is the main process module of FE. Depends: fe-common, spark-dpp