Want to know technology stack of a particular paid template before buying it..

I am interested in buying below paid template, but have a few questions before buying it:

Questions are:
(1) From the webpage, it looks like an android app is provided as well as website for admins. Want to know technology stack in which android app is built and technology stack in which website for admins is built.
(2) Is the price only one-time payment and then I can freely distribute the app built using this template to my end users. Just FYI, the app will be free.
(3) Any support is also provided during using template?
(4) We are mainly interested in android app and our team only knows java, so could you please suggest some similar app (on events creation,booking etc) based purely in java?.

Thanks a lot!

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