After applying a hotfix in the Introscope EM server the Workstation either crashes or all the collectors disconnect and reconnect

Document ID : KB000008772
Last Modified Date : 06/06/2018
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Issue:

After applying 10.5.2 HOTFIX#9  you launch the Workstation > investigator > status console, after selecting one of the Collectors icons, the workstation either crashes or all the collectors disconnect and reconnect

In the EM log you notice the below ERROR message:

[ERROR] [UnknownHub Hub Receive 13] [Manager.Cluster] Object of type "com.wily.apm.monitor.support.MonitorEventContext$ContextParameter" cannot be deserialized from loader

Environment:
10.5.2
Cause:

The above message is an indication of jar version mismatch. 

The class "com.wily.apm.monitor.support.MonitorEventContext$ContextParameter" has been removed in 10.52 HF#9 but Collector is still sending old object with this class, the message indicates that the Collector(s) has an old definition. 

Resolution:

1) Make sure you have applied the hotfix across all the Introscope Enterprise Manager instances (MOM and collectors), you can confirm this condition by reviewing the hotfix log created under the EM home directory 
 

2) After applying the hotfix, manually clear the OSGI cache:

a) Stop MOM and collectors

b) delete the osgi cache: 

go to <em install dir>/product/enterprisemanager/configuration/' folder, delete all folders except the config.ini 

go to <em install dir>/product/webview/configuration/' folder, delete all folders except the config.ini 

If you are using workstation standalone: 

go to <workstation install dir>/product/workstation/configuration/' folder, delete all folders except the config.ini 

c) go to <EM_HOME>/work - remove all files 

d) Start MOM and collectors