guys, anyone knows how to implement junit 5 in android without using any other 3rd party plugin ?

I think it means that you need to search in SO. I also think that we need to wait for AS 3.0 final released for junit 5 “working” integration. https://github.com/JetBrains/spek/issues/256

I've just search that on SO and didnt find the best way, thats why I'm asking here :D

You have to use https://github.com/mannodermaus/android-junit5. JUnit 5's gradle plugin doesn’t support android.

my question is i dont want to use any other 3rd party plugin dude ^^

You have no choice dude 🙂 Android was never a priority for JUnit 5.