Accessing multiple YAML files

So, I have been fiddling around with this for the past 5 hours and I can’t seem to figure out why I can’t access my second yaml file. I’ve been searching google for answers, and still haven’t found anything even remotely similar to what I am looking for. Now, before you ask if I have registered it onto the onEnable event, I have. The config.yml file works perfectly fine, and as I need it to. However, when I create a second yaml file, "blocks.yml", I can’t access the functions, for example:
I need to get data into the blocks.yml file, but using plugin.data.getBlocks().contains(...) the .contains() part shows an error, and it when I delete the .contains() part, my only options after the plugin.data.getBlocks() part are the try and lambda events. I am honestly extremely confused with this. I’ve even tried it without the .data part of the plugin.data.getBlocks() line, and it just doesn’t show getBlocks() altogether. Here is my config manager file;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.configuration.file.FileConfiguration;
import org.bukkit.configuration.file.YamlConfiguration;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class ConfigManager {

    private main plugin;
    private FileConfiguration config;
    private File configFile;

    private FileConfiguration blocks;
    private File blocksFile;

    public ConfigManager(main plugin) {
        this.plugin = plugin;
    }

    public void reloadConfig() {
        if (configFile == null) {
            configFile = new File(plugin.getDataFolder(), "config.yml");
        }
        config = YamlConfiguration.loadConfiguration(configFile);
        InputStream defaultStream = plugin.getResource("config.yml");
        if (defaultStream != null) {
            YamlConfiguration defaultConfig = YamlConfiguration.loadConfiguration(new InputStreamReader(defaultStream));
            config.setDefaults(defaultConfig);
        }
    }

    public void getConfig() {
        if (config == null) {
            reloadConfig();
        }
    }
    public void saveConfig() {
        if(config == null || configFile == null) {
            return;
        }
        try {
            config.save(configFile);
        } catch (IOException e) {
            plugin.getServer().getConsoleSender().sendMessage(ChatColor.RED + "Could not save config to " + this.configFile, e.toString());
        }
    }
    public void saveDefaultConfig() {
        if(configFile == null) {
            configFile = new File(plugin.getDataFolder(), "config.yml");
        }
        if(!configFile.exists()) {
            plugin.saveResource("plugin.yml", false);
        }
    }

    public void reloadBlocks() {
        if (blocksFile == null) {
            blocksFile = new File(plugin.getDataFolder(), "blocks.yml");
        }
        blocks = YamlConfiguration.loadConfiguration(blocksFile);
        InputStream defaultBlocksStream = plugin.getResource("blocks.yml");
        if (defaultBlocksStream != null) {
            YamlConfiguration defaultBlocks = YamlConfiguration.loadConfiguration(new InputStreamReader(defaultBlocksStream));
            blocks.setDefaults(defaultBlocks);
        }
    }

    public void getBlocks() {
        if (blocks == null) {
            reloadBlocks();
        }
    }
    public void saveBlocks() {
        if(blocks == null || blocksFile == null) {
            return;
        }
        try {
            blocks.save(blocksFile);
        } catch (IOException e) {
            plugin.getServer().getConsoleSender().sendMessage(ChatColor.RED + "Could not save blocks to " + this.blocksFile, e.toString());
        }
    }
    public void saveDefaultBlocks() {
        if(blocksFile == null) {
            blocksFile = new File(plugin.getDataFolder(), "blocks.yml");
        }
        if(!blocksFile.exists()) {
            plugin.saveResource("blocks.yml", false);
        }
    }
}

>Solution :

There is multiple things to say.

Your method getBlocks() return "void", so nothing. You should do something like this :

public FileConfiguration getBlocks() {
    if (blocks == null) {
        reloadBlocks();
    }
    return blocks;
}

Also, the JavaPlugin’s class already implement saveConfig() & saveDefaultConfig() method. You don’t have to copy them yourself. Do like that :

plugin.saveDefaultConfig(); // copy if not found
plugin.getConfig().set("a", "b");
plugin.saveConfig(); // save config