Experienced Programmer, Not Modding Though. Looking for Help

Hello,

So I haven't played PC Minecraft in about 3 or 4 years. Back in the day, I used to make all types of bukkit plugins and I was decently good at it too. I am playing on a survival world and I just want to add a simple mod that changes/adds drops to certain events. So for example I would want something like: 

number == rand(100);
gapple = minecrat.golden_apple();

onLeafDecayEvent event onLeafDecay(){
  if (rand>99) {
    
  loc = event.getBlock().getLocation().drop(gapple);
    
  }
}

Some of that might not be exactly perfect. It's been a while since I've coded anything but that basically the main thing I'm looking for. Any help would be much appreciated. Thanks!

EDIT: Looking for 1.14.3 help by the way

Edited July 18, 20196 yr by MrSamuelB