Workflow session throws RepositoryException on updating Workflow data - aem

Question

Trying to save some properties in the workflow metadata and below is the code snippet which I am using for the same.
try {
if (workItem.getWorkflowData().getPayloadType().equals("JCR_PATH")) {
addValuesToMetadata(workItem, workflowSession,metaDataMap);
}
MetaDataMap wfMetaData=workItem.getWorkflowData().getMetaDataMap();
Set<String> keys=metaDataMap.keySet();
for (String key : keys) {
if(key.startsWith("xyz")){
wfMetaData.put(key, metaDataMap.get(key));
}
}
workflowSession.updateWorkflowData(workItem.getWorkflow(), workItem.getWorkflowData());
} catch (Exception e) {
e.printStackTrace();
}
I am not closing the session, however it throws the following exception.
javax.jcr.RepositoryException: This session has been closed. at
org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.checkAlive(SessionDelegate.java:367)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl$ReadOperation.checkPreconditions(SessionImpl.java:110)
at
org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.perform(SessionDelegate.java:289)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl.perform(SessionImpl.java:127)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl.getItemOrNull(SessionImpl.java:228)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl.getItem(SessionImpl.java:357)
at sun.reflect.GeneratedMethodAccessor20.invoke(Unknown Source) at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606) at
org.apache.sling.jcr.base.SessionProxyHandler$SessionProxyInvocationHandler.invoke(SessionProxyHandler.java:113)
at com.sun.proxy.$Proxy0.getItem(Unknown Source) at
com.adobe.granite.workflow.core.jcr.WorkflowManager.getWorkflowNode(WorkflowManager.java:815)
at
com.adobe.granite.workflow.core.jcr.WorkflowManager.updateWorkflowData(WorkflowManager.java:326)
at
com.adobe.granite.workflow.core.WorkflowSessionImpl.updateWorkflowData(WorkflowSessionImpl.java:952)
at
com.adobe.granite.workflow.core.job.JobHandler.process(JobHandler.java:177)
at org.apache.sling.event.jobs.JobUtil$1.run(JobUtil.java:365) at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
com.adobe.granite.workflow.WorkflowException: Cannot load workItem:
/etc/workflow/instances/2015-06-18/model_1299575053804439/workItems/node7_etc_workflow_instances_2015-06-18_model_9
at
com.adobe.granite.workflow.core.jcr.WorkItemManager.updateWorkItem(WorkItemManager.java:349)
at
com.adobe.granite.workflow.core.job.JobHandler.process(JobHandler.java:180)
at org.apache.sling.event.jobs.JobUtil$1.run(JobUtil.java:365) at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745) Caused by:
javax.jcr.RepositoryException: This session has been closed. at
org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.checkAlive(SessionDelegate.java:367)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl$ReadOperation.checkPreconditions(SessionImpl.java:110)
at
org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.perform(SessionDelegate.java:289)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl.perform(SessionImpl.java:127)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl.getItemOrNull(SessionImpl.java:228)
at
org.apache.jackrabbit.oak.jcr.session.SessionImpl.getItem(SessionImpl.java:357)
at sun.reflect.GeneratedMethodAccessor20.invoke(Unknown Source) at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606) at
org.apache.sling.jcr.base.SessionProxyHandler$SessionProxyInvocationHandler.invoke(SessionProxyHandler.java:113)
at com.sun.proxy.$Proxy0.getItem(Unknown Source) at
com.adobe.granite.workflow.core.jcr.WorkItemManager.updateWorkItem(WorkItemManager.java:344)
... 5 common frames omitted
Any help is well appreciated.