Make Checker Framework.

src/main/java/ru/emotilt/antiplatka/Bot.java

@@ -14,48 +14,56 @@ import com.google.gson.Gson;
 import com.google.gson.stream.JsonReader;
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.JDABuilder;
+
+import org.jetbrains.annotations.NotNull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import ru.emotilt.antiplatka.command.types.Command;
 import ru.emotilt.antiplatka.handler.Handler;
 
 public class Bot {
-    public static Config config;
+    public static @NotNull Config config = readConfig();
-    private static Command[] commandsArray;
     private static final HashMap<String, Command> commands = new HashMap<>();
-    public static ListenerAdapter[] events;
-    private static JDA jda;
     private static final Logger logger = LoggerFactory.getLogger(Bot.class);
+
     private static final Handler<Command> commandHandler = new Handler<>(Command.class,
             "ru.emotilt.antiplatka.command");
+    private static Command[] commandsArray = commandHandler.get();
+
     private static final Handler<ListenerAdapter> eventHandler = new Handler<>(ListenerAdapter.class,
             "ru.emotilt.antiplatka.event");
-
+    public static ListenerAdapter[] events = eventHandler.get();
-    public static void main(String[] args) throws IOException, InterruptedException {
+    private static JDA jda =
-        File file = new File("./config.json");
+        JDABuilder.create(config.token, GatewayIntent.getIntents(33411))
-
-        try (FileReader reader = new FileReader(file)) {
-            JsonReader jsonreader = new JsonReader(reader);
-            Gson gson = new Gson();
-            config = gson.fromJson(jsonreader, Config.class);
-            config.enforceValidity();
-        }
-
-        logger.info("Successfully loaded config!");
-
-        commandsArray = commandHandler.get();
-        events = eventHandler.get();
-
-        jda = JDABuilder.create(config.token, GatewayIntent.getIntents(33411))
                 .disableCache(CacheFlag.ACTIVITY, CacheFlag.EMOJI, CacheFlag.STICKER,
                         CacheFlag.CLIENT_STATUS, CacheFlag.ONLINE_STATUS, CacheFlag.SCHEDULED_EVENTS)
                 .addEventListeners((Object[]) events)
                 .build();
-        jda.awaitReady();
 
+    public static void main(String[] args) throws InterruptedException {
+        jda.awaitReady();
         registerCommands();
     }
 
+    private static Config readConfig() {
+        File file = new File("./config.json");
+
+	Config cfg;
+
+        try (FileReader reader = new FileReader(file)) {
+            JsonReader jsonreader = new JsonReader(reader);
+            Gson gson = new Gson();
+            cfg = gson.fromJson(jsonreader, Config.class);
+            Objects.requireNonNull(cfg).enforceValidity();
+        } catch (IOException e) {
+            throw new ExceptionInInitializerError(e);
+	}
+
+        logger.info("Successfully loaded config!");
+
+	return cfg;
+    }
+
     private static void registerCommands() {
         logger.info("Loading commands...");
         Guild guild = Objects.requireNonNull(jda.getGuildById(config.guildId));

src/main/java/ru/emotilt/antiplatka/Config.java

@@ -1,18 +1,29 @@
 package ru.emotilt.antiplatka;
 
-import java.util.HashMap;
 import java.util.Objects;
 
 import org.jetbrains.annotations.NotNull;
 
 public class Config {
+    public static class PollDurations {
+        public final int mute;
+        public final int kick;
+        public final int add;
+
+        PollDurations(int mute, int kick, int add) {
+            this.add = add;
+            this.kick = kick;
+            this.mute = mute;
+        }
+    }
+
     public final @NotNull String token;
     public final @NotNull String guildId;
     public final int threshold;
-    public final @NotNull HashMap<String, Integer> pollDurations;
+    public final @NotNull PollDurations pollDurations;
     public final @NotNull String muteRoleId;
 
-    Config(@NotNull String token, @NotNull String guildId, int threshold, HashMap<String, Integer> pollDurations,
+    Config(@NotNull String token, @NotNull String guildId, int threshold, PollDurations pollDurations,
             String muteRoleId) {
         this.token = token;
         this.guildId = guildId;
@@ -21,10 +32,11 @@ public class Config {
         this.muteRoleId = muteRoleId;
     }
 
-    public void enforceValidity() {
+    public Config enforceValidity() {
         Objects.requireNonNull(token);
         Objects.requireNonNull(guildId);
         Objects.requireNonNull(pollDurations);
         Objects.requireNonNull(muteRoleId);
+	return this;
     }
 }

src/main/java/ru/emotilt/antiplatka/command/PollMute.java

@@ -33,7 +33,7 @@ public class PollMute extends Command {
         Member member = Objects.requireNonNull(Objects.requireNonNull(interaction.getOption("member")).getAsMember());
 
         BotPollMute.Builder pollbuilder = new BotPollMute.Builder(member,
-                Duration.ofMinutes(Bot.config.pollDurations.get("mute")));
+                Duration.ofMinutes(Bot.config.pollDurations.mute));
 
         interaction
                 .reply(pollbuilder.buildMessage(String.format("Голосование за мут %s", member.getAsMention())).build())

src/main/java/ru/emotilt/antiplatka/event/OnSlashCommandInteractionEvent.java

@@ -2,6 +2,9 @@ package ru.emotilt.antiplatka.event;
 
 import net.dv8tion.jda.api.events.interaction.command.SlashCommandInteractionEvent;
 import net.dv8tion.jda.api.hooks.ListenerAdapter;
+
+import java.util.Objects;
+
 import org.jetbrains.annotations.NotNull;
 import ru.emotilt.antiplatka.Bot;
 
@@ -10,6 +13,6 @@ public class OnSlashCommandInteractionEvent extends ListenerAdapter {
     @Override
     public void onSlashCommandInteraction(@NotNull SlashCommandInteractionEvent event) {
         super.onSlashCommandInteraction(event);
-        Bot.getCommands().get(event.getFullCommandName()).execute(event);
+        Objects.requireNonNull(Bot.getCommands().get(event.getFullCommandName())).execute(event);
     }
 }

src/main/java/ru/emotilt/antiplatka/handler/Handler.java

@@ -10,6 +10,7 @@ import java.net.URL;
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.List;
+import java.util.Objects;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 
@@ -22,7 +23,7 @@ public class Handler<T> {
         this.packageName = packageName;
     }
 
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({"unchecked", "return"})
     public T[] get() {
         try {
             List<Class<?>> classes = scanPackage(packageName);
@@ -44,7 +45,7 @@ public class Handler<T> {
     private List<Class<?>> scanPackage(String packageName) throws IOException, ClassNotFoundException {
         List<Class<?>> classes = new ArrayList<>();
         String packagePath = packageName.replace('.', '/');
-        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+        ClassLoader classLoader = Objects.requireNonNull(Thread.currentThread().getContextClassLoader());
 
         Enumeration<URL> resources = classLoader.getResources(packagePath);
         while (resources.hasMoreElements()) {

src/main/java/ru/emotilt/antiplatka/poll/BotPoll.java

@@ -2,10 +2,13 @@ package ru.emotilt.antiplatka.poll;
 
 import java.time.Duration;
 import java.util.Date;
+import java.util.Objects;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
+import org.jetbrains.annotations.Nullable;
+
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.Message;
 import net.dv8tion.jda.api.entities.channel.middleman.MessageChannel;
@@ -16,11 +19,11 @@ import net.dv8tion.jda.api.utils.messages.MessagePollData;
 import ru.emotilt.antiplatka.Bot;
 
 public abstract class BotPoll {
-    public final Message message;
+    public final @Nullable Message message;
     // TODO: Create an abstraction for targets. This means that it can have any
     // targets except the user.
     public final Member targetUser;
-    public final MessageChannel channel;
+    public final @Nullable MessageChannel channel;
     public final Date start;
     public final Duration voteDuration;
 
@@ -28,7 +31,8 @@ public abstract class BotPoll {
 
     public abstract String getEndAnnouncementText(boolean success);
 
-    public BotPoll(Message message, Member targetUser, MessageChannel channel, Date start, Duration voteDuration) {
+    @SuppressWarnings("method.invocation")
+    public BotPoll(@Nullable Message message, Member targetUser, @Nullable MessageChannel channel, Date start, Duration voteDuration) {
         this.message = message;
         this.targetUser = targetUser;
         this.channel = channel;
@@ -44,7 +48,7 @@ public abstract class BotPoll {
      * 
      * @param message A message containing a poll.
      */
-    public void schedule(Message message) {
+    public void schedule(@Nullable Message message) {
         if (isShort()) {
             ExecutorService executorService = Executors.newSingleThreadExecutor();
             executorService.submit(() -> {
@@ -54,7 +58,7 @@ public abstract class BotPoll {
                     throw new RuntimeException(e);
                 }
 
-                message.endPoll().queue();
+                Objects.requireNonNull(message).endPoll().queue();
             });
             executorService.shutdown();
         }
@@ -67,9 +71,9 @@ public abstract class BotPoll {
 
     @SuppressWarnings("unused")
     public static abstract class Builder<T extends Builder<T>> {
-        protected Message message = null;
+        protected @Nullable Message message = null;
         protected Member targetUser;
-        protected MessageChannel channel = null;
+        protected @Nullable MessageChannel channel = null;
         protected Date start = new Date();
         protected Duration voteDuration;
 

src/main/java/ru/emotilt/antiplatka/poll/BotPollMute.java

@@ -3,6 +3,8 @@ package ru.emotilt.antiplatka.poll;
 import java.time.Duration;
 import java.util.Date;
 
+import org.jetbrains.annotations.Nullable;
+
 import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.Message;
@@ -46,7 +48,7 @@ public class BotPollMute extends BotPoll {
         }
     }
 
-    public BotPollMute(Message message, Member targetUser, MessageChannel channel, Date start, Duration voteDuration) {
+    public BotPollMute(@Nullable Message message, Member targetUser, @Nullable MessageChannel channel, Date start, Duration voteDuration) {
         super(message, targetUser, channel, start, voteDuration);
     }
 }