Cluster with two instances in glassfish creating concurrency error

Question

I have two clusters and each cluster have 2 instances. When quartz scheduler is scheduled to run at 11PM in both the clusters of all the 4 instances starting at same time and making my application erroneous. Either cases are processed twice or cases are getting stuck with error.

In my scheduler program i am forming xml from table and sending that xml to web services.

Please let me know if any further information required. Please help me to resolve this concurrency error

Answer 1

The file lock technique in the below link helps me

http://www.rgagnon.com/javadetails/java-0288.html