Refactor existing code

src/main/java/META-INF/MANIFEST.MF

+Manifest-Version: 1.0
+Main-Class: emu.grasscutter.Grasscutter
+

src/main/java/emu/grasscutter/Config.java

 package emu.grasscutter;
 
-public class Config {
+public final class Config {
 	public String DispatchServerIp = "127.0.0.1";
 	public int DispatchServerPort = 443;
 	public String DispatchServerKeystorePath = "./keystore.p12";
@@ -31,14 +31,14 @@ public class Config {
 		return ServerOptions;
 	}
 	
-	public class GameRates {
+	public static class GameRates {
 		public float ADVENTURE_EXP_RATE = 1.0f;
 		public float MORA_RATE = 1.0f;
 		public float DOMAIN_DROP_RATE = 1.0f;
 	}
 	
-	public class ServerOptions {
-		public int MaxEntityLimit = 1000; // Max entity limit per world. TODO Unenforced for now
+	public static class ServerOptions {
+		public int MaxEntityLimit = 1000; // Max entity limit per world. // TODO: Enforce later.
 		public int[] WelcomeEmotes = {2007, 1002, 4010};
 		public String WelcomeMotd = "Welcome to Grasscutter emu";
 	}

src/main/java/emu/grasscutter/GenshinConstants.java

@@ -2,11 +2,10 @@ package emu.grasscutter;
 
 import java.util.Arrays;
 
-import emu.grasscutter.game.props.OpenState;
 import emu.grasscutter.utils.Position;
 import emu.grasscutter.utils.Utils;
 
-public class GenshinConstants {
+public final class GenshinConstants {
 	public static String VERSION = "2.6.0";
 	
 	public static final int MAX_TEAMS = 4;
@@ -25,9 +24,9 @@ public class GenshinConstants {
 	public static final int MAX_FRIENDS = 45;
 	public static final int MAX_FRIEND_REQUESTS = 50;
 	
-	public static final int SERVER_CONSOLE_UID = 99; // uid of the fake player used for commands
+	public static final int SERVER_CONSOLE_UID = 99; // The UID of the server console's "player".
 	
-	// Default entity ability hashes
+	// Default entity ability hashes.
 	public static final String[] DEFAULT_ABILITY_STRINGS = {
 		"Avatar_DefaultAbility_VisionReplaceDieInvincible", "Avatar_DefaultAbility_AvartarInShaderChange", "Avatar_SprintBS_Invincible", 
 		"Avatar_Freeze_Duration_Reducer", "Avatar_Attack_ReviveEnergy", "Avatar_Component_Initializer", "Avatar_FallAnthem_Achievement_Listener"

src/main/java/emu/grasscutter/Grasscutter.java

@@ -6,8 +6,8 @@ import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.InputStreamReader;
 import java.net.InetSocketAddress;
-import java.util.Arrays;
 
+import emu.grasscutter.utils.Utils;
 import org.slf4j.LoggerFactory;
 
 import com.google.gson.Gson;
@@ -22,19 +22,25 @@ import emu.grasscutter.server.game.GameServer;
 import emu.grasscutter.tools.Tools;
 import emu.grasscutter.utils.Crypto;
 
-public class Grasscutter {
-	private static Logger log = (Logger) LoggerFactory.getLogger(Grasscutter.class);
+public final class Grasscutter {
+	private static final Logger log = (Logger) LoggerFactory.getLogger(Grasscutter.class);
 	private static Config config;
 	
-	private static Gson gson = new GsonBuilder().setPrettyPrinting().create();
-	private static File configFile = new File("./config.json");
+	private static final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+	private static final File configFile = new File("./config.json");
 	
 	public static RunMode MODE = RunMode.BOTH;
 	private static DispatchServer dispatchServer;
 	private static GameServer gameServer;
 	
+	static {
+		// Load configuration.
+		Grasscutter.loadConfig();
+		// Check server structure.
+		Utils.startupCheck();
+	}
+	
     public static void main(String[] args) throws Exception {
-    	Grasscutter.loadConfig();
     	Crypto.loadKeys();
     	
 		for (String arg : args) {
@@ -48,56 +54,34 @@ public class Grasscutter {
 				case "-handbook":
 					Tools.createGmHandbook();
 					return;
-					
 			}
 		}
 		
-		// Startup
-		Grasscutter.getLogger().info("Grasscutter Emu");
+		// Initialize server.
+		Grasscutter.getLogger().info("Starting Grasscutter...");
 		
-		// Load resource files
+		// Load all resources.
 		ResourceLoader.loadAll();
-		
 		// Database
 		DatabaseManager.initialize();
 		
-		// Run servers
+		// Start servers.
 		dispatchServer = new DispatchServer();
 		dispatchServer.start();
 		
 		gameServer = new GameServer(new InetSocketAddress(getConfig().GameServerIp, getConfig().GameServerPort));
 		gameServer.start();
 		
+		// Open console.
 		startConsole();
     }
-    
-	public static Config getConfig() {
-		return config;
-	}
-	
-	public static Logger getLogger() {
-		return log;
-	}
-	
-	public static Gson getGsonFactory() {
-		return gson;
-	}
-	
-	public static DispatchServer getDispatchServer() {
-		return dispatchServer;
-	}
-	
-	public static GameServer getGameServer() {
-		return gameServer;
-	}
 	
 	public static void loadConfig() {
 		try (FileReader file = new FileReader(configFile)) {
 			config = gson.fromJson(file, Config.class);
 		} catch (Exception e) {
-			Grasscutter.config = new Config();
+			Grasscutter.config = new Config(); saveConfig();
 		}
-		saveConfig();
 	}
 	
 	public static void saveConfig() {
@@ -115,7 +99,7 @@ public class Grasscutter {
 				ServerCommands.handle(input);
 			}
 		} catch (Exception e) {
-			Grasscutter.getLogger().error("Console error:", e);
+			Grasscutter.getLogger().error("An error occurred.", e);
 		}
 	}
 	
@@ -124,4 +108,24 @@ public class Grasscutter {
 		AUTH,
 		GAME
 	}
+
+	public static Config getConfig() {
+		return config;
+	}
+
+	public static Logger getLogger() {
+		return log;
+	}
+
+	public static Gson getGsonFactory() {
+		return gson;
+	}
+
+	public static DispatchServer getDispatchServer() {
+		return dispatchServer;
+	}
+
+	public static GameServer getGameServer() {
+		return gameServer;
+	}
 }

src/main/java/emu/grasscutter/commands/Command.java

@@ -5,9 +5,9 @@ import java.lang.annotation.RetentionPolicy;
 
 @Retention(RetentionPolicy.RUNTIME) 
 public @interface Command {
-	public String[] aliases() default "";
+	String[] aliases() default "";
 	
-	public int gmLevel() default 1;
+	int gmLevel() default 1;
 	
-	public String helpText() default "";
+	String helpText() default "";
 }

src/main/java/emu/grasscutter/database/DatabaseManager.java

 package emu.grasscutter.database;
 
-import java.sql.Connection;
-import java.sql.SQLException;
-
 import com.mongodb.MongoClient;
 import com.mongodb.MongoClientURI;
 import com.mongodb.MongoCommandException;
@@ -18,12 +15,11 @@ import emu.grasscutter.game.avatar.GenshinAvatar;
 import emu.grasscutter.game.friends.Friendship;
 import emu.grasscutter.game.inventory.GenshinItem;
 
-public class DatabaseManager {
+public final class DatabaseManager {
 	private static MongoClient mongoClient;
-	private static Morphia morphia;
 	private static Datastore datastore;
 	
-	private static Class<?>[] mappedClasses = new Class<?>[] {
+	private static final Class<?>[] mappedClasses = new Class<?>[] {
 		DatabaseCounter.class, Account.class, GenshinPlayer.class, GenshinAvatar.class, GenshinItem.class, Friendship.class
 	};
     
@@ -38,15 +34,11 @@ public class DatabaseManager {
     public static MongoDatabase getDatabase() {
     	return getDatastore().getDatabase();
     }
-    
-    public static Connection getConnection() throws SQLException {
-        return null;
-    }
 	
 	public static void initialize() {
 		// Initialize
 		mongoClient = new MongoClient(new MongoClientURI(Grasscutter.getConfig().DatabaseUrl));
-		morphia = new Morphia();
+		Morphia morphia = new Morphia();
 		
 		// TODO Update when migrating to Morphia 2.0
 		morphia.getMapper().getOptions().setStoreEmpties(true);

src/main/java/emu/grasscutter/server/dispatch/DispatchHttpJsonHandler.java

@@ -7,7 +7,7 @@ import java.util.Collections;
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 
-public class DispatchHttpJsonHandler implements HttpHandler {
+public final class DispatchHttpJsonHandler implements HttpHandler {
 	private final String response;
 	
 	public DispatchHttpJsonHandler(String response) {
@@ -24,5 +24,4 @@ public class DispatchHttpJsonHandler implements HttpHandler {
         os.write(response.getBytes());
         os.close();
 	}
-
 }

src/main/java/emu/grasscutter/server/dispatch/DispatchServer.java

@@ -43,8 +43,7 @@ import emu.grasscutter.utils.Utils;
 
 import com.sun.net.httpserver.HttpServer;
 
-public class DispatchServer {
-	private HttpsServer server;
+public final class DispatchServer {
 	private final InetSocketAddress address;
 	private final Gson gson;
 	private QueryCurrRegionHttpRsp currRegion;
@@ -135,12 +134,12 @@ public class DispatchServer {
 			this.regionCurrentBase64 = Base64.getEncoder().encodeToString(parsedRegionQuery.toByteString().toByteArray());
 			this.currRegion = parsedRegionQuery;
 		} catch (Exception e) {
-			e.printStackTrace();
+			Grasscutter.getLogger().error("Error while initializing region info!", e);
 		}
 	}
 
 	public void start() throws Exception {
-		server = HttpsServer.create(getAddress(), 0);
+		HttpsServer server = HttpsServer.create(getAddress(), 0);
 		SSLContext sslContext = SSLContext.getInstance("TLS");
 		
 		try (FileInputStream fis = new FileInputStream(Grasscutter.getConfig().DispatchServerKeystorePath)) {
@@ -158,187 +157,169 @@ public class DispatchServer {
 			return;
 		}
 		
-		server.createContext("/", new HttpHandler() {
-			@Override
-			public void handle(HttpExchange t) throws IOException {
-				//Create a response form the request query parameters
-		        String response = "Hello";
-		        //Set the response header status and length
-		        t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
-		        t.sendResponseHeaders(200, response.getBytes().length);
-		        //Write the response string
-		        OutputStream os = t.getResponseBody();
-		        os.write(response.getBytes());
-		        os.close();
-			}
+		server.createContext("/", t -> {
+			//Create a response form the request query parameters
+			String response = "Hello";
+			//Set the response header status and length
+			t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
+			t.sendResponseHeaders(200, response.getBytes().length);
+			//Write the response string
+			OutputStream os = t.getResponseBody();
+			os.write(response.getBytes());
+			os.close();
 		});
 		
 		// Dispatch
-		server.createContext("/query_region_list", new HttpHandler() {
-			@Override
-			public void handle(HttpExchange t) throws IOException {
-				// Log
-				Grasscutter.getLogger().info("Client request: query_region_list");
-				// Create a response form the request query parameters
-		        String response = regionListBase64;
-		        // Set the response header status and length
-		        t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
-		        t.sendResponseHeaders(200, response.getBytes().length);
-		        // Write the response string
-		        OutputStream os = t.getResponseBody();
-		        os.write(response.getBytes());
-		        os.close();
-			}
+		server.createContext("/query_region_list", t -> {
+			// Log
+			Grasscutter.getLogger().info("Client request: query_region_list");
+			// Create a response form the request query parameters
+			String response = regionListBase64;
+			// Set the response header status and length
+			t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
+			t.sendResponseHeaders(200, response.getBytes().length);
+			// Write the response string
+			OutputStream os = t.getResponseBody();
+			os.write(response.getBytes());
+			os.close();
 		});
-		server.createContext("/query_cur_region", new HttpHandler() {
-			@Override
-			public void handle(HttpExchange t) throws IOException {
-				// Log
-				Grasscutter.getLogger().info("Client request: query_cur_region");
-				// Create a response form the request query parameters
-		        URI uri = t.getRequestURI();
-		        String response = "CAESGE5vdCBGb3VuZCB2ZXJzaW9uIGNvbmZpZw==";
-		        if (uri.getQuery() != null && uri.getQuery().length() > 0) {
-		        	response = regionCurrentBase64;
-		        }
-		        // Set the response header status and length
-		        t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
-		        t.sendResponseHeaders(200, response.getBytes().length);
-		        // Write the response string
-		        OutputStream os = t.getResponseBody();
-		        os.write(response.getBytes());
-		        os.close();
+		server.createContext("/query_cur_region", t -> {
+			// Log
+			Grasscutter.getLogger().info("Client request: query_cur_region");
+			// Create a response form the request query parameters
+			URI uri = t.getRequestURI();
+			String response = "CAESGE5vdCBGb3VuZCB2ZXJzaW9uIGNvbmZpZw==";
+			if (uri.getQuery() != null && uri.getQuery().length() > 0) {
+				response = regionCurrentBase64;
 			}
+			// Set the response header status and length
+			t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
+			t.sendResponseHeaders(200, response.getBytes().length);
+			// Write the response string
+			OutputStream os = t.getResponseBody();
+			os.write(response.getBytes());
+			os.close();
 		});
 		// Login via account
-		server.createContext("/hk4e_global/mdk/shield/api/login", new HttpHandler() {
-			@Override
-			public void handle(HttpExchange t) throws IOException {
-				// Get post data
-				LoginAccountRequestJson requestData = null;
-				try {
-					String body = Utils.toString(t.getRequestBody());
-					requestData = getGsonFactory().fromJson(body, LoginAccountRequestJson.class);
-				} catch (Exception e) {
-					
-				}
-				// Create response json
-				if (requestData == null) {
-					return;
-				}
-				LoginResultJson responseData = new LoginResultJson();
-				
-				// Login
-				Account account = DatabaseHelper.getAccountByName(requestData.account);
+		server.createContext("/hk4e_global/mdk/shield/api/login", t -> {
+			// Get post data
+			LoginAccountRequestJson requestData = null;
+			try {
+				String body = Utils.toString(t.getRequestBody());
+				requestData = getGsonFactory().fromJson(body, LoginAccountRequestJson.class);
+			} catch (Exception e) {
 				
-				// Test
-				if (account == null) {
-					responseData.retcode = -201;
-					responseData.message = "Username not found.";
-				} else {
-					responseData.message = "OK";
-					responseData.data.account.uid = account.getId();
-					responseData.data.account.token = account.generateSessionKey();
-					responseData.data.account.email = account.getEmail();
-				}
-				
-				// Create a response
-		        String response = getGsonFactory().toJson(responseData);
-		        // Set the response header status and length
-		        t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
-		        t.sendResponseHeaders(200, response.getBytes().length);
-		        // Write the response string
-		        OutputStream os = t.getResponseBody();
-		        os.write(response.getBytes());
-		        os.close();
 			}
+			// Create response json
+			if (requestData == null) {
+				return;
+			}
+			LoginResultJson responseData = new LoginResultJson();
+			
+			// Login
+			Account account = DatabaseHelper.getAccountByName(requestData.account);
+			
+			// Test
+			if (account == null) {
+				responseData.retcode = -201;
+				responseData.message = "Username not found.";
+			} else {
+				responseData.message = "OK";
+				responseData.data.account.uid = account.getId();
+				responseData.data.account.token = account.generateSessionKey();
+				responseData.data.account.email = account.getEmail();
+			}
+			
+			// Create a response
+			String response = getGsonFactory().toJson(responseData);
+			// Set the response header status and length
+			t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
+			t.sendResponseHeaders(200, response.getBytes().length);
+			// Write the response string
+			OutputStream os = t.getResponseBody();
+			os.write(response.getBytes());
+			os.close();
 		});
 		// Login via token
-		server.createContext("/hk4e_global/mdk/shield/api/verify", new HttpHandler() {
-			@Override
-			public void handle(HttpExchange t) throws IOException {
-				// Get post data
-				LoginTokenRequestJson requestData = null;
-				try {
-					String body = Utils.toString(t.getRequestBody());
-					requestData = getGsonFactory().fromJson(body, LoginTokenRequestJson.class);
-				} catch (Exception e) {
-					
-				}
-				// Create response json
-				if (requestData == null) {
-					return;
-				}
-				LoginResultJson responseData = new LoginResultJson();
-
-				// Login
-				Account account = DatabaseHelper.getAccountById(requestData.uid);
-				
-				// Test
-				if (account == null || !account.getSessionKey().equals(requestData.token)) {
-					responseData.retcode = -111;
-					responseData.message = "Game account cache information error";
-				} else {
-					responseData.message = "OK";
-					responseData.data.account.uid = requestData.uid;
-					responseData.data.account.token = requestData.token;
-					responseData.data.account.email = account.getEmail();
-				}
+		server.createContext("/hk4e_global/mdk/shield/api/verify", t -> {
+			// Get post data
+			LoginTokenRequestJson requestData = null;
+			try {
+				String body = Utils.toString(t.getRequestBody());
+				requestData = getGsonFactory().fromJson(body, LoginTokenRequestJson.class);
+			} catch (Exception e) {
 				
-				// Create a response
-		        String response = getGsonFactory().toJson(responseData);
-		        // Set the response header status and length
-		        t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
-		        t.sendResponseHeaders(200, response.getBytes().length);
-		        // Write the response string
-		        OutputStream os = t.getResponseBody();
-		        os.write(response.getBytes());
-		        os.close();
 			}
+			// Create response json
+			if (requestData == null) {
+				return;
+			}
+			LoginResultJson responseData = new LoginResultJson();
+
+			// Login
+			Account account = DatabaseHelper.getAccountById(requestData.uid);
+			
+			// Test
+			if (account == null || !account.getSessionKey().equals(requestData.token)) {
+				responseData.retcode = -111;
+				responseData.message = "Game account cache information error";
+			} else {
+				responseData.message = "OK";
+				responseData.data.account.uid = requestData.uid;
+				responseData.data.account.token = requestData.token;
+				responseData.data.account.email = account.getEmail();
+			}
+			
+			// Create a response
+			String response = getGsonFactory().toJson(responseData);
+			// Set the response header status and length
+			t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
+			t.sendResponseHeaders(200, response.getBytes().length);
+			// Write the response string
+			OutputStream os = t.getResponseBody();
+			os.write(response.getBytes());
+			os.close();
 		});
 		// Exchange for combo token
-		server.createContext("/hk4e_global/combo/granter/login/v2/login", new HttpHandler() {
-			@Override
-			public void handle(HttpExchange t) throws IOException {
-				// Get post data
-				ComboTokenReqJson requestData = null;
-				try {
-					String body = Utils.toString(t.getRequestBody());
-					requestData = getGsonFactory().fromJson(body, ComboTokenReqJson.class);
-				} catch (Exception e) {
-					
-				}
-				// Create response json
-				if (requestData == null || requestData.data == null) {
-					return;
-				}
-				LoginTokenData loginData = getGsonFactory().fromJson(requestData.data, LoginTokenData.class); // Get login data
-				ComboTokenResJson responseData = new ComboTokenResJson();
-
-				// Login
-				Account account = DatabaseHelper.getAccountById(loginData.uid);
-				
-				// Test
-				if (account == null || !account.getSessionKey().equals(loginData.token)) {
-					responseData.retcode = -201;
-					responseData.message = "Wrong session key.";
-				} else {
-					responseData.message = "OK";
-					responseData.data.open_id = loginData.uid;
-					responseData.data.combo_id = "157795300";
-					responseData.data.combo_token = account.generateLoginToken();
-				}
+		server.createContext("/hk4e_global/combo/granter/login/v2/login", t -> {
+			// Get post data
+			ComboTokenReqJson requestData = null;
+			try {
+				String body = Utils.toString(t.getRequestBody());
+				requestData = getGsonFactory().fromJson(body, ComboTokenReqJson.class);
+			} catch (Exception e) {
 				
-				// Create a response
-		        String response = getGsonFactory().toJson(responseData);
-		        // Set the response header status and length
-		        t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
-		        t.sendResponseHeaders(200, response.getBytes().length);
-		        // Write the response string
-		        OutputStream os = t.getResponseBody();
-		        os.write(response.getBytes());
-		        os.close();
 			}
+			// Create response json
+			if (requestData == null || requestData.data == null) {
+				return;
+			}
+			LoginTokenData loginData = getGsonFactory().fromJson(requestData.data, LoginTokenData.class); // Get login data
+			ComboTokenResJson responseData = new ComboTokenResJson();
+
+			// Login
+			Account account = DatabaseHelper.getAccountById(loginData.uid);
+			
+			// Test
+			if (account == null || !account.getSessionKey().equals(loginData.token)) {
+				responseData.retcode = -201;
+				responseData.message = "Wrong session key.";
+			} else {
+				responseData.message = "OK";
+				responseData.data.open_id = loginData.uid;
+				responseData.data.combo_id = "157795300";
+				responseData.data.combo_token = account.generateLoginToken();
+			}
+			
+			// Create a response
+			String response = getGsonFactory().toJson(responseData);
+			// Set the response header status and length
+			t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
+			t.sendResponseHeaders(200, response.getBytes().length);
+			// Write the response string
+			OutputStream os = t.getResponseBody();
+			os.write(response.getBytes());
+			os.close();
 		});
 		// Agreement and Protocol
 		server.createContext( // hk4e-sdk-os.hoyoverse.com
@@ -420,19 +401,16 @@ public class DispatchServer {
 				"/crash/dataUpload", 
 				new DispatchHttpJsonHandler("{\"code\":0}")
 		);
-		uploadLogServer.createContext("/gacha", new HttpHandler() {
-			@Override
-			public void handle(HttpExchange t) throws IOException {
-				//Create a response form the request query parameters
-		        String response = "<!doctype html><html lang=\"en\"><head><title>Gacha</title></head><body></body></html>";
-		        //Set the response header status and length
-		        t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
-		        t.sendResponseHeaders(200, response.getBytes().length);
-		        //Write the response string
-		        OutputStream os = t.getResponseBody();
-		        os.write(response.getBytes());
-		        os.close();
-			}
+		uploadLogServer.createContext("/gacha", t -> {
+			//Create a response form the request query parameters
+			String response = "<!doctype html><html lang=\"en\"><head><title>Gacha</title></head><body></body></html>";
+			//Set the response header status and length
+			t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
+			t.sendResponseHeaders(200, response.getBytes().length);
+			//Write the response string
+			OutputStream os = t.getResponseBody();
+			os.write(response.getBytes());
+			os.close();
 		});
 		uploadLogServer.start();
 		Grasscutter.getLogger().info("Log server (log-upload-os) started on port " + 80);

src/main/java/emu/grasscutter/tools/Dumpers.java

@@ -8,10 +8,8 @@ import emu.grasscutter.game.props.OpenState;
 import emu.grasscutter.net.proto.GetGachaInfoRspOuterClass.GetGachaInfoRsp;
 import emu.grasscutter.net.proto.GetShopRspOuterClass.GetShopRsp;
 import emu.grasscutter.net.proto.OpenStateUpdateNotifyOuterClass.OpenStateUpdateNotify;
-import emu.grasscutter.utils.FileUtils;
 
-public class Dumpers {
-	
+public final class Dumpers {
 	public static void extractBanner(byte[] data) throws Exception {
 		GetGachaInfoRsp proto = GetGachaInfoRsp.parseFrom(data);
 		System.out.println(proto);

src/main/java/emu/grasscutter/tools/Tools.java

@@ -5,6 +5,7 @@ import java.io.FileWriter;
 import java.io.PrintWriter;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -20,7 +21,7 @@ import emu.grasscutter.data.def.AvatarData;
 import emu.grasscutter.data.def.ItemData;
 import emu.grasscutter.data.def.MonsterData;
 
-public class Tools {
+public final class Tools {
 	
 	@SuppressWarnings("deprecation")
 	public static void createGmHandbook() throws Exception {
@@ -40,7 +41,7 @@ public class Tools {
 			writer.println("// Genshin Impact " + GenshinConstants.VERSION + " GM Handbook");
 			writer.println("// Created " + dtf.format(now) + System.lineSeparator() + System.lineSeparator());
 			
-			list = GenshinData.getAvatarDataMap().keySet().stream().collect(Collectors.toList());
+			list = new ArrayList<>(GenshinData.getAvatarDataMap().keySet());
 			Collections.sort(list); 
 			 
 			writer.println("// Avatars");
@@ -51,7 +52,7 @@ public class Tools {
 			
 			writer.println();
 			
-			list = GenshinData.getItemDataMap().keySet().stream().collect(Collectors.toList());
+			list = new ArrayList<>(GenshinData.getItemDataMap().keySet());
 			Collections.sort(list); 
 			
 			writer.println("// Items");
@@ -63,7 +64,7 @@ public class Tools {
 			writer.println();
 			
 			writer.println("// Monsters");
-			list = GenshinData.getMonsterDataMap().keySet().stream().collect(Collectors.toList());
+			list = new ArrayList<>(GenshinData.getMonsterDataMap().keySet());
 			Collections.sort(list); 
 			
 			for (Integer id : list) {

src/main/java/emu/grasscutter/utils/Crypto.java

@@ -7,8 +7,8 @@ import emu.grasscutter.Grasscutter;
 import emu.grasscutter.net.proto.GetPlayerTokenRspOuterClass.GetPlayerTokenRsp;
 import emu.grasscutter.net.proto.QueryCurrRegionHttpRspOuterClass.QueryCurrRegionHttpRsp;
 
-public class Crypto {
-	private static SecureRandom secureRandom = new SecureRandom();
+public final class Crypto {
+	private static final SecureRandom secureRandom = new SecureRandom();
 	public static final long ENCRYPT_SEED = Long.parseUnsignedLong("11468049314633205968");
 	public static byte[] ENCRYPT_SEED_BUFFER = new byte[0];
 
@@ -37,8 +37,7 @@ public class Crypto {
 			FileUtils.write(Grasscutter.getConfig().KEY_FOLDER + "secretKeyBuffer.bin", p.getSecretKeyBuffer().toByteArray());
 			Grasscutter.getLogger().info("Secret Key: " + p.getSecretKey());
 		} catch (Exception e) {
-			// TODO Auto-generated catch block
-			e.printStackTrace();
+			Grasscutter.getLogger().error("Crypto error.", e);
 		}
 	}
 	
@@ -47,7 +46,7 @@ public class Crypto {
 			QueryCurrRegionHttpRsp p = QueryCurrRegionHttpRsp.parseFrom(Base64.getDecoder().decode(data));
 			FileUtils.write(Grasscutter.getConfig().KEY_FOLDER + "dispatchSeed.bin", p.getRegionInfo().getSecretKey().toByteArray());
 		} catch (Exception e) {
-			e.printStackTrace();
+			Grasscutter.getLogger().error("Crypto error.", e);
 		}
 	}
 	

src/main/java/emu/grasscutter/utils/FileUtils.java

 package emu.grasscutter.utils;
 
+import emu.grasscutter.Grasscutter;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
-public class FileUtils {
-	
+public final class FileUtils {
 	public static void write(String dest, byte[] bytes) {
 		Path path = Paths.get(dest);
 		
 		try {
 			Files.write(path, bytes);
 		} catch (IOException e) {
-			// TODO Auto-generated catch block
-			e.printStackTrace();
+			Grasscutter.getLogger().warn("Failed to write file: " + dest);
 		}
 	}
 	
@@ -27,8 +27,7 @@ public class FileUtils {
 		try {
 			return Files.readAllBytes(path);
 		} catch (IOException e) {
-			// TODO Auto-generated catch block
-			e.printStackTrace();
+			Grasscutter.getLogger().warn("Failed to read file: " + path);
 		}
 		
 		return new byte[0];

src/main/java/emu/grasscutter/utils/ProtoHelper.java

@@ -3,7 +3,7 @@ package emu.grasscutter.utils;
 import emu.grasscutter.game.props.PlayerProperty;
 import emu.grasscutter.net.proto.PropValueOuterClass.PropValue;
 
-public class ProtoHelper {
+public final class ProtoHelper {
 	public static PropValue newPropValue(PlayerProperty key, int value) {
 		return PropValue.newBuilder().setType(key.getId()).setIval(value).setVal(value).build();
 	}

src/main/java/emu/grasscutter/utils/Utils.java

 package emu.grasscutter.utils;
 
-import java.io.BufferedInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
 import java.util.Random;
 
+import emu.grasscutter.Config;
 import emu.grasscutter.Grasscutter;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
+import org.slf4j.Logger;
 
-public class Utils {
+@SuppressWarnings({"UnusedReturnValue", "BooleanMethodIsAlwaysInverted"})
+public final class Utils {
 	public static final Random random = new Random();
 	
 	public static int randomRange(int min, int max) {
@@ -76,4 +78,77 @@ public class Utils {
 	    }
 	    return v7;
 	}
+
+	/**
+	 * Checks if a file exists on the file system.
+	 * @param path The path to the file.
+	 * @return True if the file exists, false otherwise.
+	 */
+	public static boolean fileExists(String path) {
+		return new File(path).exists();
+	}
+
+	/**
+	 * Creates a folder on the file system.
+	 * @param path The path to the folder.
+	 * @return True if the folder was created, false otherwise.
+	 */
+	public static boolean createFolder(String path) {
+		return new File(path).mkdirs();
+	}
+
+	/**
+	 * Copies a file from the archive's resources to the file system.
+	 * @param resource The path to the resource.
+	 * @param destination The path to copy the resource to.
+	 * @return True if the file was copied, false otherwise.
+	 */
+	public static boolean copyFromResources(String resource, String destination) {
+		try (InputStream stream = Grasscutter.class.getResourceAsStream(resource)) {
+			if(stream == null) {
+				Grasscutter.getLogger().warn("Could not find resource: " + resource);
+				return false;
+			}
+
+			Files.copy(stream, new File(destination).toPath(), StandardCopyOption.REPLACE_EXISTING);
+			return true;
+		} catch (Exception e) {
+			Grasscutter.getLogger().warn("Unable to copy resource " + resource + " to " + destination, e);
+			return false;
+		}
+	}
+
+	/**
+	 * Checks for required files and folders before startup.
+	 */
+	public static void startupCheck() {
+		Config config = Grasscutter.getConfig();
+		Logger logger = Grasscutter.getLogger();
+		boolean exit = false;
+
+		String resourcesFolder = config.RESOURCE_FOLDER;
+		String dataFolder = config.DATA_FOLDER;
+
+		// Check for resources folder.
+		if(!fileExists(resourcesFolder)) {
+			logger.info("Creating resources folder...");
+			logger.info("Place a copy of 'GenshinData' in the resources folder.");
+			createFolder(resourcesFolder); exit = true;
+		}
+
+		// Check for GenshinData.
+		if(!fileExists(resourcesFolder + "BinOutput") ||
+				!fileExists(resourcesFolder + "ExcelBinOutput")) {
+			logger.info("Place a copy of 'GenshinData' in the resources folder.");
+			exit = true;
+		}
+
+		// Check for game data.
+		if(!fileExists(dataFolder))
+			createFolder(dataFolder);
+		if(!fileExists(dataFolder + "AbilityEmbryos.json"))
+			copyFromResources("data/AbilityEmbryos.json", dataFolder);
+
+		if(exit) System.exit(1);
+	}
 }