Error injecting constructor, java.lang.RuntimeException: VaadinSessionLock.create() must be called from the main thread.

Products

• CA Automic Workload Automation - Automation Engine

Issue/Introduction

Error starting delegate com.uc4.ecc.plugins.ae.ProcessAutomationPluginInstance*************************************************
com.google.inject.ProvisionException: Unable to provision, see the following errors:

1) Error injecting constructor, java.lang.RuntimeException: VaadinSessionLock.create() must be called from the main thread.
  at com.uc4.ecc.framework.entrypoint.core.lock.VaadinSessionLockUtil.<init>(Unknown Source)
  while locating com.uc4.ecc.framework.entrypoint.core.lock.VaadinSessionLockUtil
  at com.uc4.ecc.framework.core.inject.util.BinderUtils.bindContextService(BinderUtils.java:188)
  while locating com.uc4.ecc.framework.core.async.ILockUtility

Environment

Automation Engine 21.0.x

JAVA : 11

Resolution

These errors are usually caused by a conflict in the compiled data in the work (Tomcat cache) folder. With a change in Java, the work folder should be deleted.

Since the data is going to the work directory, this leads to such errors. To resolve the issue follow the below steps

Resolution:

 (a) stop Tomcat 
 (b) delete the work directory
 (c) do not save it anywhere, delete it.  This gets recreated when Tomcat is restarted.

FYI:  These errors are noticed with JAVA 11 versions