Help to fix Water

Hey !
I work on a skyblock server and I want to fix water and vines that falling into the void, because I don't want to have LAGs ! I try BlockFromTo event to check if BlockTo is null or AIR but it doesn't work ! Can you help me ??
It's very important !

Code:

package fr.earthsky.fix;

import org.bukkit.Material;
import org.bukkit.block.Block;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockFromToEvent;
import org.bukkit.plugin.java.JavaPlugin;


public class Fix extends JavaPlugin implements Listener{
    @EventHandler
    public void FixWater(BlockFromToEvent e){
        Block block = e.getBlock();
        System.out.println(block);
        if(block.getType().equals(Material.WATER) || block.getType().equals(Material.STATIONARY_WATER)){
            Block blockFormedOn = e.getToBlock();
            if(blockFormedOn.getType() == null || blockFormedOn.getType() == Material.AIR){
                e.setCancelled(true);
            }else{
                System.out.println(blockFormedOn);
            }
        }else{
            System.out.println(block);
        }
    }
}