Iserena1021

i have downloaded the newest java (8.0.3330.2) and forge 1.8.9 i ran java and installed it but when i run forge 1.8.9 it says "unable to install java" then "there are errors in the following switches" and names where my forge file is and says "check that the commands are valid and try again" i've tried to delete and re-download everything but the same thing happens, is it because i've already downloaded forge 1.12.2?