Firebase Java error

when i run firebase emulators:start it gives me this error

Firestore Emulator has exited because java is not installed, you can install it from,
   stopping all running emulators

Hey there,

this error seems very helpful to me.
It also says how you can solve it.

i solved it can you tell me how can i solve the other problem them you commented on the Unhandled Rejection firebase error.