I am try to create a simple application in android studio version 4.1.1 and I have the JDK version 15 but when I start with a plain project template, in the main activity it is showing the override fun() and in the YOUTUBE when I see someone's code there is protected void instead of override fun() and when I write a function in my code starting with public void it is showing me the error in the code so can anyone help me to get out of this issue thanks in advance