Caused by: java.lang.UnsupportedClassVersionError:

Hi all,

My usecase:

  • Use flowable/flowable-ui:6.8.0 as Admin flowable app
  • Use flowable/flowable-rest:7.0.0 as Rest flowable app
    These apps use common PostgreSQL DB user
  • A custom Java Delegate class is copied to both above apps.
  • To start the workflow & control flow (user task), I use .NET app by calling flowable’s REST api

The issue:

  • Sometimes the workflow work fine & it reach the End state
  • Simetimes, we got the below issue “Caused by: java.lang.UnsupportedClassVersionError: com/fecredit/flowable/servicetask/RestServiceTaskImpl has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 55.0”

I found that this issue happen because the Java Delegate class is complied in Java 17 while the flowable Admin is running in Java 11.

My question is:

  • When I using 02 dockers container like this, we have 02 workflow engine ? Is it correct ?
  • If yes, Can I force it run under REST engine only ?

Thank.

Anyone can help me ?

Hey @ngthanhvu,

It is not because of Flowable Admin. It is because of the Flowable UI Task application that is in flowable/flowable-ui. I would advise against using both the Flowable 6.8 UI Task application and Flowable 7 Rest application. Those 2 are not compatible and there can be other problems if you run them with the same DB.

If you want you can keep create your own Admin app using the starters from 6.8 for that and only run flowable/flowable-rest:7.1.0 from Flowable.

Cheers,
Filip