Move from GSON to Jackson, cleanup code warnings, move to javax.annotation annotations

build.gradle

@@ -35,7 +35,9 @@ dependencies {
     implementation group: 'com.electronwill.night-config', name: 'toml', version: nightconfig_version
     implementation group: 'net.sf.jopt-simple', name: 'jopt-simple', version: jopt_version
     implementation group: 'com.google.guava', name: 'guava', version: guava_version
-    implementation group: 'com.google.code.gson', name: 'gson', version: gson_version
+    implementation group: 'com.fasterxml.jackson.core', name: 'jackson-core', version: jackson_version
+    implementation group: 'com.fasterxml.jackson.core', name: 'jackson-annotations', version: jackson_version
+    implementation group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version: jackson_version
     implementation group: 'org.apache.logging.log4j', name: 'log4j-to-slf4j', version: log4j_bridge_version
     implementation group: 'ch.qos.logback', name: 'logback-classic', version: logback_version
     implementation group: 'com.mojang', name: 'brigadier', version: brigadier_version

gradle.properties

@@ -5,7 +5,7 @@ jda_version=4.2.0_207
 nightconfig_version=3.6.3
 jopt_version=6.0-alpha-3
 guava_version=29.0-jre
-gson_version=2.8.6
+jackson_version=2.11.2
 log4j_bridge_version=2.13.3
 logback_version=1.3.0-alpha5
 brigadier_version=1.0.17

src/main/java/sciwhiz12/janitor/BotStartup.java

@@ -1,5 +1,6 @@
 package sciwhiz12.janitor;
 
+import com.google.common.base.Preconditions;
 import net.dv8tion.jda.api.JDABuilder;
 import net.dv8tion.jda.api.OnlineStatus;
 import net.dv8tion.jda.api.entities.Activity;
@@ -12,7 +13,6 @@ import sciwhiz12.janitor.config.BotOptions;
 
 import java.util.EnumSet;
 
-import static com.google.common.base.Preconditions.checkArgument;
 import static sciwhiz12.janitor.Logging.JANITOR;
 
 public class BotStartup {
@@ -21,7 +21,7 @@ public class BotStartup {
 
         BotOptions options = new BotOptions(args);
         BotConfig config = new BotConfig(options);
-        checkArgument(!config.getToken().isEmpty(), "Supply a client token through config or command line");
+        Preconditions.checkArgument(!config.getToken().isEmpty(), "Supply a client token through config or command line");
 
         JANITOR.info("Building bot instance and connecting to Discord...");
 

src/main/java/sciwhiz12/janitor/GuildStorage.java

@@ -1,8 +1,6 @@
 package sciwhiz12.janitor;
 
 import com.google.common.base.Preconditions;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import net.dv8tion.jda.api.entities.Guild;
 import sciwhiz12.janitor.storage.IStorage;
 
@@ -19,8 +17,6 @@ import java.util.function.Supplier;
 import static java.nio.file.StandardOpenOption.*;
 
 public class GuildStorage {
-    private static final Gson GSON = new GsonBuilder().setPrettyPrinting().serializeNulls().create();
-
     private final JanitorBot bot;
     private final Path mainFolder;
     private final Map<Guild, Map<String, IStorage>> guildStorage = new IdentityHashMap<>();
@@ -35,9 +31,9 @@ public class GuildStorage {
         return bot;
     }
 
+    @SuppressWarnings("unchecked")
     public <T extends IStorage> T getOrCreate(Guild guild, String key, Supplier<T> defaultSupplier) {
         final Map<String, IStorage> storageMap = guildStorage.computeIfAbsent(guild, g -> new HashMap<>());
-        //noinspection unchecked
         return (T) storageMap.computeIfAbsent(key, k -> load(guild, key, defaultSupplier.get()));
     }
 

src/main/java/sciwhiz12/janitor/commands/moderation/BanCommand.java

@@ -8,7 +8,6 @@ import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.MessageChannel;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import sciwhiz12.janitor.commands.BaseCommand;
 import sciwhiz12.janitor.commands.CommandRegistry;
 import sciwhiz12.janitor.commands.util.ModerationHelper;
@@ -16,6 +15,7 @@ import sciwhiz12.janitor.commands.util.ModerationHelper;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Objects;
+import javax.annotation.Nullable;
 
 import static com.mojang.brigadier.arguments.IntegerArgumentType.getInteger;
 import static com.mojang.brigadier.arguments.IntegerArgumentType.integer;

src/main/java/sciwhiz12/janitor/commands/moderation/KickCommand.java

@@ -8,7 +8,6 @@ import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.MessageChannel;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import sciwhiz12.janitor.commands.BaseCommand;
 import sciwhiz12.janitor.commands.CommandRegistry;
 import sciwhiz12.janitor.commands.util.CommandHelper;
@@ -17,6 +16,7 @@ import sciwhiz12.janitor.commands.util.ModerationHelper;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Objects;
+import javax.annotation.Nullable;
 
 import static com.mojang.brigadier.arguments.StringArgumentType.getString;
 import static com.mojang.brigadier.arguments.StringArgumentType.greedyString;

src/main/java/sciwhiz12/janitor/commands/moderation/NoteCommand.java

@@ -9,7 +9,6 @@ import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.MessageChannel;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import sciwhiz12.janitor.commands.BaseCommand;
 import sciwhiz12.janitor.commands.CommandRegistry;
 import sciwhiz12.janitor.moderation.notes.NoteEntry;
@@ -22,6 +21,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Predicate;
+import javax.annotation.Nullable;
 
 import static com.mojang.brigadier.arguments.IntegerArgumentType.getInteger;
 import static com.mojang.brigadier.arguments.IntegerArgumentType.integer;
@@ -160,10 +160,9 @@ public class NoteCommand extends BaseCommand {
             case PERFORMER: {
                 predicate = predicate.and(e -> e.getValue().getPerformer().getIdLong() == performer.getIdLong());
             }
+            case NONE: {}
         }
 
-        final OffsetDateTime dateTime = OffsetDateTime.now();
-
         if (!performer.hasPermission(NOTE_PERMISSION))
             channel.sendMessage(
                 messages().MODERATION.ERRORS.performerInsufficientPermissions(performer, NOTE_PERMISSION).build(getBot()))
@@ -188,8 +187,6 @@ public class NoteCommand extends BaseCommand {
         final Guild guild = ctx.getSource().getGuild();
         final Member performer = Objects.requireNonNull(ctx.getSource().getMember());
 
-        final OffsetDateTime dateTime = OffsetDateTime.now();
-
         if (!performer.hasPermission(NOTE_PERMISSION))
             channel.sendMessage(
                 messages().MODERATION.ERRORS.performerInsufficientPermissions(performer, NOTE_PERMISSION).build(getBot()))

src/main/java/sciwhiz12/janitor/commands/moderation/UnwarnCommand.java

@@ -8,15 +8,14 @@ import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.MessageChannel;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import sciwhiz12.janitor.commands.BaseCommand;
 import sciwhiz12.janitor.commands.CommandRegistry;
 import sciwhiz12.janitor.moderation.warns.WarningEntry;
 import sciwhiz12.janitor.moderation.warns.WarningStorage;
 
-import java.time.OffsetDateTime;
 import java.util.EnumSet;
 import java.util.Objects;
+import javax.annotation.Nullable;
 
 import static sciwhiz12.janitor.commands.util.CommandHelper.argument;
 import static sciwhiz12.janitor.commands.util.CommandHelper.literal;
@@ -52,8 +51,6 @@ public class UnwarnCommand extends BaseCommand {
         final Member performer = Objects.requireNonNull(ctx.getSource().getMember());
         int caseID = IntegerArgumentType.getInteger(ctx, "caseId");
 
-        final OffsetDateTime dateTime = OffsetDateTime.now();
-
         if (!performer.hasPermission(WARN_PERMISSION))
             channel.sendMessage(
                 messages().MODERATION.ERRORS.performerInsufficientPermissions(performer, WARN_PERMISSION).build(getBot()))

src/main/java/sciwhiz12/janitor/commands/moderation/WarnListCommand.java

@@ -14,7 +14,6 @@ import sciwhiz12.janitor.commands.CommandRegistry;
 import sciwhiz12.janitor.moderation.warns.WarningEntry;
 import sciwhiz12.janitor.moderation.warns.WarningStorage;
 
-import java.time.OffsetDateTime;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Map;
@@ -88,8 +87,6 @@ public class WarnListCommand extends BaseCommand {
             predicate = predicate.and(e -> e.getValue().getPerformer().getIdLong() == mod.getIdLong());
         }
 
-        final OffsetDateTime dateTime = OffsetDateTime.now();
-
         if (!performer.hasPermission(WARN_PERMISSION))
             channel.sendMessage(
                 messages().MODERATION.ERRORS.performerInsufficientPermissions(performer, WARN_PERMISSION).build(getBot()))

src/main/java/sciwhiz12/janitor/commands/util/ModerationHelper.java

@@ -4,11 +4,11 @@ import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.User;
 import net.dv8tion.jda.api.requests.restaction.AuditableRestAction;
-import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
+import javax.annotation.Nullable;
 
 import static sciwhiz12.janitor.utils.Util.nameFor;
 

src/main/java/sciwhiz12/janitor/config/BotConfig.java

@@ -4,11 +4,11 @@ import com.electronwill.nightconfig.core.file.CommentedFileConfig;
 import com.electronwill.nightconfig.core.file.FileNotFoundAction;
 import com.electronwill.nightconfig.core.file.FileWatcher;
 import com.electronwill.nightconfig.toml.TomlFormat;
-import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.io.IOException;
 import java.nio.file.Path;
 import java.util.Optional;
+import javax.annotation.Nullable;
 
 import static sciwhiz12.janitor.Logging.CONFIG;
 import static sciwhiz12.janitor.Logging.JANITOR;

src/main/java/sciwhiz12/janitor/moderation/notes/NoteEntry.java

@@ -1,18 +1,19 @@
 package sciwhiz12.janitor.moderation.notes;
 
-import com.google.gson.JsonDeserializationContext;
+import com.fasterxml.jackson.core.JsonGenerator;
-import com.google.gson.JsonDeserializer;
+import com.fasterxml.jackson.core.JsonParser;
-import com.google.gson.JsonElement;
+import com.fasterxml.jackson.databind.DeserializationContext;
-import com.google.gson.JsonObject;
+import com.fasterxml.jackson.databind.JsonNode;
-import com.google.gson.JsonParseException;
+import com.fasterxml.jackson.databind.SerializerProvider;
-import com.google.gson.JsonSerializationContext;
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
-import com.google.gson.JsonSerializer;
+import com.fasterxml.jackson.databind.ser.std.StdSerializer;
 import net.dv8tion.jda.api.entities.User;
 import sciwhiz12.janitor.JanitorBot;
 
-import java.lang.reflect.Type;
+import java.io.IOException;
 import java.time.OffsetDateTime;
 import java.util.Objects;
+import java.util.function.Supplier;
 
 public class NoteEntry {
     private final User performer;
@@ -59,32 +60,42 @@ public class NoteEntry {
         return Objects.hash(getPerformer(), getTarget(), getDateTime(), getContents());
     }
 
-    public static class Serializer implements JsonDeserializer<NoteEntry>, JsonSerializer<NoteEntry> {
+    public static class Serializer extends StdSerializer<NoteEntry> {
-        private final JanitorBot bot;
+        private static final long serialVersionUID = 1L;
 
-        public Serializer(JanitorBot bot) {
+        public Serializer() {
+            super(NoteEntry.class);
+        }
+
+        @Override
+        public void serialize(NoteEntry value, JsonGenerator gen, SerializerProvider provider) throws IOException {
+            gen.writeStartObject();
+            gen.writeNumberField("performer", value.getPerformer().getIdLong());
+            gen.writeNumberField("target", value.getTarget().getIdLong());
+            gen.writeStringField("dateTime", value.getDateTime().toString());
+            gen.writeStringField("contents", value.getContents());
+            gen.writeEndObject();
+        }
+    }
+
+    public static class Deserializer extends StdDeserializer<NoteEntry> {
+        private static final long serialVersionUID = 1L;
+
+        private final Supplier<JanitorBot> bot;
+
+        public Deserializer(Supplier<JanitorBot> bot) {
+            super(NoteEntry.class);
             this.bot = bot;
         }
 
         @Override
-        public NoteEntry deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+        public NoteEntry deserialize(JsonParser p, DeserializationContext ctx) throws IOException {
-            throws JsonParseException {
+            final JsonNode obj = ctx.readTree(p);
-            final JsonObject obj = json.getAsJsonObject();
+            User performer = bot.get().getDiscord().retrieveUserById(obj.get("performer").asLong()).complete();
-            final User performer = bot.getDiscord().retrieveUserById(obj.get("performer").getAsLong()).complete();
+            User target = bot.get().getDiscord().retrieveUserById(obj.get("target").asLong()).complete();
-            final User target = bot.getDiscord().retrieveUserById(obj.get("target").getAsLong()).complete();
+            OffsetDateTime dateTime = OffsetDateTime.parse(obj.get("dateTime").asText());
-            final OffsetDateTime dateTime = OffsetDateTime.parse(obj.get("dateTime").getAsString());
+            String contents = obj.get("contents").asText();
-            final String reason = obj.get("contents").getAsString();
+            return new NoteEntry(performer, target, dateTime, contents);
-            return new NoteEntry(performer, target, dateTime, reason);
-        }
-
-        @Override
-        public JsonElement serialize(NoteEntry src, Type typeOfSrc, JsonSerializationContext context) {
-            final JsonObject obj = new JsonObject();
-            obj.addProperty("performer", src.getPerformer().getId());
-            obj.addProperty("target", src.getTarget().getId());
-            obj.addProperty("dateTime", src.getDateTime().toString());
-            obj.addProperty("contents", src.getContents());
-            return obj;
         }
     }
 }

src/main/java/sciwhiz12/janitor/moderation/notes/NoteStorage.java

@@ -1,40 +1,36 @@
 package sciwhiz12.janitor.moderation.notes;
 
 import com.electronwill.nightconfig.core.utils.ObservedMap;
-import com.google.gson.Gson;
+import com.fasterxml.jackson.core.type.TypeReference;
-import com.google.gson.GsonBuilder;
+import com.fasterxml.jackson.databind.JsonNode;
-import com.google.gson.JsonElement;
+import com.fasterxml.jackson.databind.ObjectMapper;
-import com.google.gson.JsonObject;
+import com.fasterxml.jackson.databind.module.SimpleModule;
-import com.google.gson.reflect.TypeToken;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import net.dv8tion.jda.api.entities.Guild;
 import net.dv8tion.jda.api.entities.User;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import sciwhiz12.janitor.GuildStorage;
 import sciwhiz12.janitor.JanitorBot;
 import sciwhiz12.janitor.storage.JsonStorage;
 
-import java.lang.reflect.Type;
+import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
+import javax.annotation.Nullable;
 
 public class NoteStorage extends JsonStorage {
-    private static final Type NOTE_MAP_TYPE = new TypeToken<Map<Integer, NoteEntry>>() {}.getType();
+    private static final TypeReference<Map<Integer, NoteEntry>> NOTE_MAP_TYPE = new TypeReference<>() {};
     public static final String STORAGE_KEY = "notes";
 
     public static NoteStorage get(GuildStorage storage, Guild guild) {
         return storage.getOrCreate(guild, STORAGE_KEY, () -> new NoteStorage(storage.getBot()));
     }
 
-    private final Gson gson;
     private final JanitorBot bot;
     private int lastID = 1;
     private final Map<Integer, NoteEntry> notes = new ObservedMap<>(new HashMap<>(), this::markDirty);
 
     public NoteStorage(JanitorBot bot) {
         this.bot = bot;
-        this.gson = new GsonBuilder()
-            .registerTypeAdapter(NoteEntry.class, new NoteEntry.Serializer(bot))
-            .create();
     }
 
     public JanitorBot getBot() {
@@ -52,8 +48,8 @@ public class NoteStorage extends JsonStorage {
         return notes.get(noteID);
     }
 
-    public NoteEntry removeNote(int noteID) {
+    public void removeNote(int noteID) {
-        return notes.remove(noteID);
+        notes.remove(noteID);
     }
 
     public int getAmountOfNotes(User target) {
@@ -67,18 +63,27 @@ public class NoteStorage extends JsonStorage {
     }
 
     @Override
-    public JsonElement save() {
+    protected void initialize(ObjectMapper mapper) {
-        JsonObject obj = new JsonObject();
+        super.initialize(mapper);
-        obj.addProperty("lastNoteID", lastID);
+        mapper.registerModule(
-        obj.add("notes", gson.toJsonTree(notes));
+            new SimpleModule()
+                .addSerializer(NoteEntry.class, new NoteEntry.Serializer())
+                .addDeserializer(NoteEntry.class, new NoteEntry.Deserializer(this::getBot))
+        );
+    }
+
+    @Override
+    public JsonNode save(ObjectMapper mapper) {
+        final ObjectNode obj = mapper.createObjectNode();
+        obj.put("lastNoteID", lastID);
+        obj.set("notes", mapper.valueToTree(notes));
         return obj;
     }
 
     @Override
-    public void load(JsonElement in) {
+    public void load(JsonNode in, ObjectMapper mapper) throws IOException {
-        final JsonObject obj = in.getAsJsonObject();
+        lastID = in.get("lastNoteID").asInt();
-        lastID = obj.get("lastNoteID").getAsInt();
+        final Map<Integer, NoteEntry> loaded = mapper.readerFor(NOTE_MAP_TYPE).readValue(in.get("notes"));
-        final Map<Integer, NoteEntry> loaded = gson.fromJson(obj.get("notes"), NOTE_MAP_TYPE);
         notes.clear();
         notes.putAll(loaded);
     }

src/main/java/sciwhiz12/janitor/moderation/warns/WarningEntry.java

@@ -1,18 +1,19 @@
 package sciwhiz12.janitor.moderation.warns;
 
-import com.google.gson.JsonDeserializationContext;
+import com.fasterxml.jackson.core.JsonGenerator;
-import com.google.gson.JsonDeserializer;
+import com.fasterxml.jackson.core.JsonParser;
-import com.google.gson.JsonElement;
+import com.fasterxml.jackson.databind.DeserializationContext;
-import com.google.gson.JsonObject;
+import com.fasterxml.jackson.databind.JsonNode;
-import com.google.gson.JsonParseException;
+import com.fasterxml.jackson.databind.SerializerProvider;
-import com.google.gson.JsonSerializationContext;
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
-import com.google.gson.JsonSerializer;
+import com.fasterxml.jackson.databind.ser.std.StdSerializer;
 import net.dv8tion.jda.api.entities.User;
 import sciwhiz12.janitor.JanitorBot;
 
-import java.lang.reflect.Type;
+import java.io.IOException;
 import java.time.OffsetDateTime;
 import java.util.Objects;
+import java.util.function.Supplier;
 import javax.annotation.Nullable;
 
 public class WarningEntry {
@@ -62,35 +63,42 @@ public class WarningEntry {
         return Objects.hash(getPerformer(), getWarned(), getDateTime(), getReason());
     }
 
-    public static class Serializer implements JsonDeserializer<WarningEntry>, JsonSerializer<WarningEntry> {
+    public static class Serializer extends StdSerializer<WarningEntry> {
-        private final JanitorBot bot;
+        private static final long serialVersionUID = 1L;
 
-        public Serializer(JanitorBot bot) {
+        public Serializer() {
+            super(WarningEntry.class);
+        }
+
+        @Override
+        public void serialize(WarningEntry value, JsonGenerator gen, SerializerProvider provider) throws IOException {
+            gen.writeStartObject();
+            gen.writeNumberField("performer", value.getPerformer().getIdLong());
+            gen.writeNumberField("warned", value.getWarned().getIdLong());
+            gen.writeStringField("dateTime", value.getDateTime().toString());
+            gen.writeStringField("reason", value.getReason());
+            gen.writeEndObject();
+        }
+    }
+
+    public static class Deserializer extends StdDeserializer<WarningEntry> {
+        private static final long serialVersionUID = 1L;
+
+        private final Supplier<JanitorBot> bot;
+
+        public Deserializer(Supplier<JanitorBot> bot) {
+            super(WarningEntry.class);
             this.bot = bot;
         }
 
         @Override
-        public WarningEntry deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+        public WarningEntry deserialize(JsonParser p, DeserializationContext ctx) throws IOException {
-            throws JsonParseException {
+            final JsonNode obj = ctx.readTree(p);
-            final JsonObject obj = json.getAsJsonObject();
+            User performer = bot.get().getDiscord().retrieveUserById(obj.get("performer").asLong()).complete();
-            final User warned = bot.getDiscord().retrieveUserById(obj.get("warned").getAsLong()).complete();
+            User warned = bot.get().getDiscord().retrieveUserById(obj.get("warned").asLong()).complete();
-            final User performer = bot.getDiscord().retrieveUserById(obj.get("performer").getAsLong()).complete();
+            OffsetDateTime dateTime = OffsetDateTime.parse(obj.get("dateTime").asText());
-            final OffsetDateTime dateTime = OffsetDateTime.parse(obj.get("dateTime").getAsString());
+            String contents = obj.get("reason").asText();
-            @Nullable
+            return new WarningEntry(performer, warned, dateTime, contents);
-            final String reason = obj.has("reason") ? obj.get("reason").getAsString() : null;
-            return new WarningEntry(warned, performer, dateTime, reason);
-        }
-
-        @Override
-        public JsonElement serialize(WarningEntry src, Type typeOfSrc, JsonSerializationContext context) {
-            final JsonObject obj = new JsonObject();
-            obj.addProperty("warned", src.getWarned().getId());
-            obj.addProperty("performer", src.getPerformer().getId());
-            obj.addProperty("dateTime", src.getDateTime().toString());
-            if (src.getReason() != null) {
-                obj.addProperty("reason", src.getReason());
-            }
-            return obj;
         }
     }
 }

src/main/java/sciwhiz12/janitor/moderation/warns/WarningStorage.java

@@ -1,39 +1,35 @@
 package sciwhiz12.janitor.moderation.warns;
 
 import com.electronwill.nightconfig.core.utils.ObservedMap;
-import com.google.gson.Gson;
+import com.fasterxml.jackson.core.type.TypeReference;
-import com.google.gson.GsonBuilder;
+import com.fasterxml.jackson.databind.JsonNode;
-import com.google.gson.JsonElement;
+import com.fasterxml.jackson.databind.ObjectMapper;
-import com.google.gson.JsonObject;
+import com.fasterxml.jackson.databind.module.SimpleModule;
-import com.google.gson.reflect.TypeToken;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import net.dv8tion.jda.api.entities.Guild;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import sciwhiz12.janitor.GuildStorage;
 import sciwhiz12.janitor.JanitorBot;
 import sciwhiz12.janitor.storage.JsonStorage;
 
-import java.lang.reflect.Type;
+import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
+import javax.annotation.Nullable;
 
 public class WarningStorage extends JsonStorage {
-    private static final Type WARNING_MAP_TYPE = new TypeToken<Map<Integer, WarningEntry>>() {}.getType();
+    private static final TypeReference<Map<Integer, WarningEntry>> WARNING_MAP_TYPE = new TypeReference<>() {};
     public static final String STORAGE_KEY = "warnings";
 
     public static WarningStorage get(GuildStorage storage, Guild guild) {
         return storage.getOrCreate(guild, STORAGE_KEY, () -> new WarningStorage(storage.getBot()));
     }
 
-    private final Gson gson;
     private final JanitorBot bot;
     private int lastID = 1;
     private final Map<Integer, WarningEntry> warnings = new ObservedMap<>(new HashMap<>(), this::markDirty);
 
     public WarningStorage(JanitorBot bot) {
         this.bot = bot;
-        this.gson = new GsonBuilder()
-            .registerTypeAdapter(WarningEntry.class, new WarningEntry.Serializer(bot))
-            .create();
     }
 
     public JanitorBot getBot() {
@@ -51,8 +47,8 @@ public class WarningStorage extends JsonStorage {
         return warnings.get(caseID);
     }
 
-    public WarningEntry removeWarning(int caseID) {
+    public void removeWarning(int caseID) {
-        return warnings.remove(caseID);
+        warnings.remove(caseID);
     }
 
     public Map<Integer, WarningEntry> getWarnings() {
@@ -60,18 +56,27 @@ public class WarningStorage extends JsonStorage {
     }
 
     @Override
-    public JsonElement save() {
+    protected void initialize(ObjectMapper mapper) {
-        JsonObject obj = new JsonObject();
+        super.initialize(mapper);
-        obj.addProperty("lastCaseID", lastID);
+        mapper.registerModule(
-        obj.add("warnings", gson.toJsonTree(warnings));
+            new SimpleModule()
+                .addSerializer(WarningEntry.class, new WarningEntry.Serializer())
+                .addDeserializer(WarningEntry.class, new WarningEntry.Deserializer(this::getBot))
+        );
+    }
+
+    @Override
+    public JsonNode save(ObjectMapper mapper) {
+        final ObjectNode obj = mapper.createObjectNode();
+        obj.put("lastCaseID", lastID);
+        obj.set("warnings", mapper.valueToTree(warnings));
         return obj;
     }
 
     @Override
-    public void load(JsonElement in) {
+    public void load(JsonNode in, ObjectMapper mapper) throws IOException {
-        final JsonObject obj = in.getAsJsonObject();
+        lastID = in.get("lastCaseID").asInt();
-        lastID = obj.get("lastCaseID").getAsInt();
+        final Map<Integer, WarningEntry> loaded = mapper.convertValue(in.get("warnings"), WARNING_MAP_TYPE);
-        final Map<Integer, WarningEntry> loaded = gson.fromJson(obj.get("warnings"), WARNING_MAP_TYPE);
         warnings.clear();
         warnings.putAll(loaded);
     }

src/main/java/sciwhiz12/janitor/msg/MessageBuilder.java

@@ -25,7 +25,6 @@ public class MessageBuilder {
         this(new EmbedBuilder(), new HashMap<>());
     }
 
-    @SuppressWarnings("CopyConstructorMissesField")
     public MessageBuilder(MessageBuilder copy) {
         this(new EmbedBuilder(copy.embedBuilder), new HashMap<>(copy.substitutions));
     }

src/main/java/sciwhiz12/janitor/msg/Moderation.java

@@ -3,7 +3,6 @@ package sciwhiz12.janitor.msg;
 import net.dv8tion.jda.api.Permission;
 import net.dv8tion.jda.api.entities.Member;
 import net.dv8tion.jda.api.entities.User;
-import org.checkerframework.checker.nullness.qual.Nullable;
 import sciwhiz12.janitor.moderation.notes.NoteEntry;
 import sciwhiz12.janitor.moderation.warns.WarningEntry;
 
@@ -12,6 +11,7 @@ import java.time.ZoneOffset;
 import java.util.EnumSet;
 import java.util.Map;
 import java.util.stream.Collectors;
+import javax.annotation.Nullable;
 
 import static java.time.format.DateTimeFormatter.RFC_1123_DATE_TIME;
 

src/main/java/sciwhiz12/janitor/msg/Translations.java

@@ -1,13 +1,11 @@
 package sciwhiz12.janitor.msg;
 
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.io.Resources;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
-import com.google.gson.reflect.TypeToken;
 import sciwhiz12.janitor.JanitorBot;
 
 import java.io.InputStreamReader;
-import java.lang.reflect.Type;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Collections;
@@ -18,13 +16,13 @@ import static sciwhiz12.janitor.Logging.JANITOR;
 import static sciwhiz12.janitor.Logging.TRANSLATIONS;
 
 public class Translations {
-    private static final Gson GSON = new GsonBuilder().create();
     private static final String DEFAULT_TRANSLATIONS_RESOURCE = "english.json";
-    private static final Type MAP_TYPE = new TypeToken<Map<String, String>>() {}.getType();
+    private static final TypeReference<Map<String, String>> MAP_TYPE = new TypeReference<>() {};
 
     private final JanitorBot bot;
     private final Path translationsFile;
     private final Map<String, String> translations = new HashMap<>();
+    private final ObjectMapper jsonMapper = new ObjectMapper();
 
     public Translations(JanitorBot bot, Path translationsFile) {
         this.bot = bot;
@@ -40,7 +38,7 @@ public class Translations {
         }
         try {
             JANITOR.debug(TRANSLATIONS, "Loading translations from file {}", translationsFile);
-            Map<String, String> trans = GSON.fromJson(Files.newBufferedReader(translationsFile), MAP_TYPE);
+            Map<String, String> trans = jsonMapper.readValue(Files.newBufferedReader(translationsFile), MAP_TYPE);
             translations.clear();
             translations.putAll(trans);
             JANITOR.info(TRANSLATIONS, "Loaded {} translations from file {}", translations.size(), translationsFile);
@@ -55,7 +53,7 @@ public class Translations {
         try {
             JANITOR.debug(TRANSLATIONS, "Loading default english translations");
             // noinspection UnstableApiUsage
-            Map<String, String> trans = GSON.fromJson(
+            Map<String, String> trans = jsonMapper.readValue(
                 new InputStreamReader(Resources.getResource(DEFAULT_TRANSLATIONS_RESOURCE).openStream()),
                 MAP_TYPE);
             translations.clear();

src/main/java/sciwhiz12/janitor/storage/IStorage.java

@@ -1,5 +1,6 @@
 package sciwhiz12.janitor.storage;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.Writer;
 
@@ -7,7 +8,7 @@ public interface IStorage {
 
     boolean dirty();
 
-    void write(Writer output);
+    void write(Writer output) throws IOException;
 
-    void read(Reader input);
+    void read(Reader input) throws IOException;
 }

src/main/java/sciwhiz12/janitor/storage/JsonStorage.java

@@ -1,30 +1,35 @@
 package sciwhiz12.janitor.storage;
 
-import com.google.gson.Gson;
+import com.fasterxml.jackson.databind.JsonNode;
-import com.google.gson.GsonBuilder;
+import com.fasterxml.jackson.databind.ObjectMapper;
-import com.google.gson.JsonElement;
+import com.fasterxml.jackson.databind.SerializationFeature;
-import com.google.gson.JsonParser;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.Writer;
 
 public abstract class JsonStorage extends AbstractStorage {
-    public static final Gson GSON = new GsonBuilder()
+    protected final ObjectMapper jsonMapper = new ObjectMapper()
-        .serializeNulls()
+        .enable(SerializationFeature.INDENT_OUTPUT)
-        .setPrettyPrinting()
+        .enable(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS);
-        .create();
 
-    public abstract JsonElement save();
+    protected JsonStorage() {
+        initialize(jsonMapper);
+    }
 
-    public abstract void load(JsonElement object);
+    protected void initialize(ObjectMapper mapper) {}
+
+    public abstract JsonNode save(ObjectMapper mapper);
+
+    public abstract void load(JsonNode object, ObjectMapper mapper) throws IOException;
 
     @Override
-    public void write(Writer input) {
+    public void write(Writer input) throws IOException {
-        GSON.toJson(save(), input);
+        jsonMapper.writeTree(jsonMapper.createGenerator(input), save(jsonMapper));
     }
 
     @Override
-    public void read(Reader input) {
+    public void read(Reader input) throws IOException {
-        load(JsonParser.parseReader(input));
+        load(jsonMapper.readTree(input), jsonMapper);
     }
 }

src/main/java/sciwhiz12/janitor/utils/StringReaderUtil.java

@@ -37,8 +37,6 @@ public class StringReaderUtil {
     }
 
     private static final char SYNTAX_ESCAPE = '\\';
-    private static final char SYNTAX_DOUBLE_QUOTE = '"';
-    private static final char SYNTAX_SINGLE_QUOTE = '\'';
     public static String readStringUntil(StringReader reader, char terminator) throws CommandSyntaxException {
         final StringBuilder result = new StringBuilder();
         boolean escaped = false;

src/main/java/sciwhiz12/janitor/utils/Util.java

@@ -55,8 +55,8 @@ public class Util {
         return user.getName().concat("#").concat(user.getDiscriminator());
     }
 
-    public static <Success, Error> BiConsumer<Success, Error> handle(final Consumer<Success> success,
+    public static <Success, Err> BiConsumer<Success, Err> handle(final Consumer<Success> success,
-        final Consumer<Error> exceptionally) {
+        final Consumer<Err> exceptionally) {
         return (suc, ex) -> {
             if (ex == null) {
                 success.accept(suc);