public class DropList implements CommandExecutor {

    FileConfiguration config = Main.plugin.getConfig();

    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {

        if(args.length == 0) {

            List<Material> blocksPlaced = Arrays.stream(Material.values())
                    .filter(Material::isBlock)
                    .collect(Collectors.toList());

            List<Material> shuffledBlocks = Arrays.stream(Material.values())
                    .collect(Collectors.toList());
            Collections.shuffle(shuffledBlocks);

            Map<Material, Material> blockTypeMappings = Streams.zip(blocksPlaced.stream(), shuffledBlocks.stream(), AbstractMap.SimpleEntry::new)
                    .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));

            File configFile = new File("plugins/Randomizer/dictionary.yml");
            if (configFile.exists())
                configFile.delete();
            try {
                configFile.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
            FileConfiguration config = YamlConfiguration.loadConfiguration(configFile);
            for (Map.Entry<Material, Material> entry : blockTypeMappings.entrySet())
                config.set(entry.getKey().toString(), entry.getValue().toString());


        }else{
            sender.sendMessage("§cBitte benutze nur §6/randomize§c!");
        }

        return false;
    }

---------------------------------------------------------------------------------------------------------------------------------------


public class BlockDestroyedListener implements Listener{

    FileConfiguration config = Main.plugin.getConfig();

    @EventHandler
    public void onBreak(BlockBreakEvent e){
        Block block = e.getBlock();
        e.setCancelled(true);
        block.setType(Material.AIR);



    }
}