How can I make the player jump when they reach the edge of a block?

[Frontear]

@SubscribeEvent public void onTick(TickEvent.PlayerTickEvent event) {
	if (event.phase != TickEvent.Phase.START) return; // see EntityPlayer.onUpdate
	if (event.player instanceof EntityPlayerSP) {
		final EntityPlayerSP player = (EntityPlayerSP) event.player;
		if (player.world.getCollidingBoundingBoxes(player, player.getEntityBoundingBox().addCoord(player.motionX, player.motionY, player.motionZ)).isEmpty()) {
			player.jump();
		}
    }
}

I  wanted to be able to extend the functionality of AutoJump, by adding a feature which would make the player jump if they reached the end of a block. I was given this code by someone on discord, and while I've got a vague understanding of how it works, it does not fully operate right. Pretty consistently, it will burn in lava if I try to use it when there is a lava below the player and when it attempts to jump, which is definitely not wanted. How can I implement something like that?

Edited May 27, 2019 by Frontear