I am not able to find java class in the service task in activiti diagram

[ankit_goods10]

I am not able to find java class in the service task in activiti diagram

[ryandawson]

I guess you're using the v6 Kickstart App. There is an article about using delegates with the enterprise version - https://community.alfresco.com/community/bpm/blog/2016/11/15/activiti-enterprise-developer-series-se...  . You should find most of the content of the article applicable to the open source Kickstart App too.