Introduce @ParametersAreNonnullByDefault

application/build.gradle

@@ -39,6 +39,7 @@ shadowJar {
 }
 
 dependencies {
+    implementation 'com.google.code.findbugs:jsr305:3.0.2'
     implementation 'org.jetbrains:annotations:23.0.0'
 
     implementation project(':database')

application/src/main/java/org/togetherjava/tjbot/Application.java

@@ -2,20 +2,17 @@
 
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.JDABuilder;
-import net.dv8tion.jda.api.requests.GatewayIntent;
 import net.dv8tion.jda.api.events.interaction.command.SlashCommandInteractionEvent;
-import org.jetbrains.annotations.NotNull;
+import net.dv8tion.jda.api.requests.GatewayIntent;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.togetherjava.tjbot.commands.Features;
+import org.togetherjava.tjbot.commands.SlashCommandAdapter;
 import org.togetherjava.tjbot.commands.system.BotCore;
 import org.togetherjava.tjbot.config.Config;
 import org.togetherjava.tjbot.db.Database;
-import org.togetherjava.tjbot.commands.SlashCommandAdapter;
 
 import javax.security.auth.login.LoginException;
-
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -114,8 +111,7 @@ private static void onShutdown() {
         logger.info("Bot has been stopped");
     }
 
-    private static void onUncaughtException(@NotNull Thread failingThread,
-            @NotNull Throwable failure) {
+    private static void onUncaughtException(Thread failingThread, Throwable failure) {
         logger.error("Unknown error in thread {}.", failingThread.getName(), failure);
     }
 

application/src/main/java/org/togetherjava/tjbot/commands/Features.java

@@ -1,7 +1,6 @@
 package org.togetherjava.tjbot.commands;
 
 import net.dv8tion.jda.api.JDA;
-import org.jetbrains.annotations.NotNull;
 import org.togetherjava.tjbot.commands.basic.PingCommand;
 import org.togetherjava.tjbot.commands.basic.RoleSelectCommand;
 import org.togetherjava.tjbot.commands.basic.SuggestionsUpDownVoter;
@@ -32,6 +31,7 @@
 import org.togetherjava.tjbot.moderation.ModAuditLogWriter;
 import org.togetherjava.tjbot.routines.ModAuditLogRoutine;
 
+import javax.annotation.Nonnull;
 import java.util.ArrayList;
 import java.util.Collection;
 
@@ -59,8 +59,8 @@ private Features() {
      * @param config the configuration features should use
      * @return a collection of all features
      */
-    public static @NotNull Collection<Feature> createFeatures(@NotNull JDA jda,
-            @NotNull Database database, @NotNull Config config) {
+    @Nonnull
+    public static Collection<Feature> createFeatures(JDA jda, Database database, Config config) {
         TagSystem tagSystem = new TagSystem(database);
         ModerationActionsStore actionsStore = new ModerationActionsStore(database);
         ModAuditLogWriter modAuditLogWriter = new ModAuditLogWriter(config);

application/src/main/java/org/togetherjava/tjbot/commands/MessageReceiver.java

@@ -2,8 +2,8 @@
 
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
 import net.dv8tion.jda.api.events.message.MessageUpdateEvent;
-import org.jetbrains.annotations.NotNull;
 
+import javax.annotation.Nonnull;
 import java.util.regex.Pattern;
 
 /**
@@ -28,7 +28,7 @@ public interface MessageReceiver extends Feature {
      *
      * @return the pattern matching the names of relevant channels
      */
-    @NotNull
+    @Nonnull
     Pattern getChannelNamePattern();
 
     /**
@@ -38,7 +38,7 @@ public interface MessageReceiver extends Feature {
      * @param event the event that triggered this, containing information about the corresponding
      *        message that was sent and received
      */
-    void onMessageReceived(@NotNull MessageReceivedEvent event);
+    void onMessageReceived(MessageReceivedEvent event);
 
     /**
      * Triggered by the core system whenever an existing message was edited in a text channel of a
@@ -47,5 +47,5 @@ public interface MessageReceiver extends Feature {
      * @param event the event that triggered this, containing information about the corresponding
      *        message that was edited
      */
-    void onMessageUpdated(@NotNull MessageUpdateEvent event);
+    void onMessageUpdated(MessageUpdateEvent event);
 }

application/src/main/java/org/togetherjava/tjbot/commands/MessageReceiverAdapter.java

@@ -2,8 +2,8 @@
 
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
 import net.dv8tion.jda.api.events.message.MessageUpdateEvent;
-import org.jetbrains.annotations.NotNull;
 
+import javax.annotation.Nonnull;
 import java.util.regex.Pattern;
 
 /**
@@ -24,24 +24,25 @@ public abstract class MessageReceiverAdapter implements MessageReceiver {
      * @param channelNamePattern the pattern matching names of channels interested in, only messages
      *        from matching channels will be received
      */
-    protected MessageReceiverAdapter(@NotNull Pattern channelNamePattern) {
+    protected MessageReceiverAdapter(Pattern channelNamePattern) {
         this.channelNamePattern = channelNamePattern;
     }
 
     @Override
-    public final @NotNull Pattern getChannelNamePattern() {
+    @Nonnull
+    public final Pattern getChannelNamePattern() {
         return channelNamePattern;
     }
 
     @SuppressWarnings("NoopMethodInAbstractClass")
     @Override
-    public void onMessageReceived(@NotNull MessageReceivedEvent event) {
+    public void onMessageReceived(MessageReceivedEvent event) {
         // Adapter does not react by default, subclasses may change this behavior
     }
 
     @SuppressWarnings("NoopMethodInAbstractClass")
     @Override
-    public void onMessageUpdated(@NotNull MessageUpdateEvent event) {
+    public void onMessageUpdated(MessageUpdateEvent event) {
         // Adapter does not react by default, subclasses may change this behavior
     }
 }

application/src/main/java/org/togetherjava/tjbot/commands/Routine.java

@@ -1,8 +1,8 @@
 package org.togetherjava.tjbot.commands;
 
 import net.dv8tion.jda.api.JDA;
-import org.jetbrains.annotations.NotNull;
 
+import javax.annotation.Nonnull;
 import java.util.concurrent.TimeUnit;
 
 /**
@@ -24,15 +24,15 @@ public interface Routine extends Feature {
      *
      * @return the schedule of this routine
      */
-    @NotNull
+    @Nonnull
     Schedule createSchedule();
 
     /**
      * Triggered by the core system on the schedule defined by {@link #createSchedule()}.
      *
      * @param jda the JDA instance the bot is operating with
      */
-    void runRoutine(@NotNull JDA jda);
+    void runRoutine(JDA jda);
 
     /**
      * The schedule of routines.
@@ -46,8 +46,7 @@ public interface Routine extends Feature {
      * @param unit the time unit for both, {@link #initialDuration} and {@link #duration}, e.g.
      *        seconds
      */
-    record Schedule(@NotNull ScheduleMode mode, long initialDuration, long duration,
-            @NotNull TimeUnit unit) {
+    record Schedule(ScheduleMode mode, long initialDuration, long duration, TimeUnit unit) {
     }
 
 

application/src/main/java/org/togetherjava/tjbot/commands/SlashCommand.java

@@ -9,11 +9,11 @@
 import net.dv8tion.jda.api.interactions.commands.build.SlashCommandData;
 import net.dv8tion.jda.api.interactions.components.ComponentInteraction;
 import net.dv8tion.jda.api.interactions.components.buttons.ButtonStyle;
-import org.jetbrains.annotations.NotNull;
 import org.togetherjava.tjbot.commands.componentids.ComponentId;
 import org.togetherjava.tjbot.commands.componentids.ComponentIdGenerator;
 import org.togetherjava.tjbot.commands.componentids.Lifespan;
 
+import javax.annotation.Nonnull;
 import java.util.List;
 
 /**
@@ -49,7 +49,7 @@ public interface SlashCommand extends UserInteractor {
      *
      * @return the description of the command
      */
-    @NotNull
+    @Nonnull
     String getDescription();
 
     /**
@@ -59,7 +59,7 @@ public interface SlashCommand extends UserInteractor {
      *
      * @return the visibility of the command
      */
-    @NotNull
+    @Nonnull
     SlashCommandVisibility getVisibility();
 
     /**
@@ -77,7 +77,7 @@ public interface SlashCommand extends UserInteractor {
      *
      * @return the command data of this command
      */
-    @NotNull
+    @Nonnull
     SlashCommandData getData();
 
     /**
@@ -118,5 +118,5 @@ public interface SlashCommand extends UserInteractor {
      *
      * @param event the event that triggered this
      */
-    void onSlashCommand(@NotNull SlashCommandInteractionEvent event);
+    void onSlashCommand(SlashCommandInteractionEvent event);
 }

application/src/main/java/org/togetherjava/tjbot/commands/SlashCommandAdapter.java

@@ -9,13 +9,13 @@
 import net.dv8tion.jda.api.interactions.commands.build.Commands;
 import net.dv8tion.jda.api.interactions.commands.build.OptionData;
 import net.dv8tion.jda.api.interactions.commands.build.SlashCommandData;
-import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Range;
 import org.jetbrains.annotations.Unmodifiable;
 import org.togetherjava.tjbot.commands.componentids.ComponentId;
 import org.togetherjava.tjbot.commands.componentids.ComponentIdGenerator;
 import org.togetherjava.tjbot.commands.componentids.Lifespan;
 
+import javax.annotation.Nonnull;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
@@ -55,7 +55,7 @@
  *         }
  *
  *         @Override
- *         public void onSlashCommand(@NotNull SlashCommandInteractionEvent event) {
+ *         public void onSlashCommand(SlashCommandInteractionEvent event) {
  *             event.reply("Pong!").queue();
  *         }
  *     }
@@ -80,7 +80,7 @@ public abstract class SlashCommandAdapter implements SlashCommand {
      *        {@link SlashCommandData#setDescription(String)}
      * @param visibility the visibility of the command
      */
-    protected SlashCommandAdapter(@NotNull String name, @NotNull String description,
+    protected SlashCommandAdapter(String name, String description,
             SlashCommandVisibility visibility) {
         this.name = name;
         this.description = description;
@@ -90,40 +90,43 @@ protected SlashCommandAdapter(@NotNull String name, @NotNull String description,
     }
 
     @Override
-    public final @NotNull String getName() {
+    @Nonnull
+    public final String getName() {
         return name;
     }
 
     @Override
-    public final @NotNull String getDescription() {
+    @Nonnull
+    public final String getDescription() {
         return description;
     }
 
     @Override
-    public final @NotNull SlashCommandVisibility getVisibility() {
+    @Nonnull
+    public final SlashCommandVisibility getVisibility() {
         return visibility;
     }
 
     @Override
-    public final @NotNull SlashCommandData getData() {
+    @Nonnull
+    public final SlashCommandData getData() {
         return data;
     }
 
     @Override
-    public final void acceptComponentIdGenerator(@NotNull ComponentIdGenerator generator) {
+    public final void acceptComponentIdGenerator(ComponentIdGenerator generator) {
         componentIdGenerator = generator;
     }
 
     @SuppressWarnings("NoopMethodInAbstractClass")
     @Override
-    public void onButtonClick(@NotNull ButtonInteractionEvent event, @NotNull List<String> args) {
+    public void onButtonClick(ButtonInteractionEvent event, List<String> args) {
         // Adapter does not react by default, subclasses may change this behavior
     }
 
     @SuppressWarnings("NoopMethodInAbstractClass")
     @Override
-    public void onSelectionMenu(@NotNull SelectMenuInteractionEvent event,
-            @NotNull List<String> args) {
+    public void onSelectionMenu(SelectMenuInteractionEvent event, List<String> args) {
         // Adapter does not react by default, subclasses may change this behavior
     }
 
@@ -142,7 +145,8 @@ public void onSelectionMenu(@NotNull SelectMenuInteractionEvent event,
      * @return the generated component ID
      */
     @SuppressWarnings("OverloadedVarargsMethod")
-    protected final @NotNull String generateComponentId(@NotNull String... args) {
+    @Nonnull
+    protected final String generateComponentId(String... args) {
         return generateComponentId(Lifespan.REGULAR, args);
     }
 
@@ -159,8 +163,8 @@ public void onSelectionMenu(@NotNull SelectMenuInteractionEvent event,
      * @return the generated component ID
      */
     @SuppressWarnings({"OverloadedVarargsMethod", "WeakerAccess"})
-    protected final @NotNull String generateComponentId(@NotNull Lifespan lifespan,
-            @NotNull String... args) {
+    @Nonnull
+    protected final String generateComponentId(Lifespan lifespan, String... args) {
         return Objects.requireNonNull(componentIdGenerator)
             .generate(new ComponentId(getName(), Arrays.asList(args)), lifespan);
     }
@@ -190,8 +194,9 @@ public void onSelectionMenu(@NotNull SelectMenuInteractionEvent event,
      * @return the generated list of options
      */
     @Unmodifiable
-    protected static @NotNull List<OptionData> generateMultipleOptions(
-            @NotNull OptionData optionData, @Range(from = 1, to = 25) int amount) {
+    @Nonnull
+    protected static List<OptionData> generateMultipleOptions(OptionData optionData,
+            @Range(from = 1, to = 25) int amount) {
         String baseName = optionData.getName();
 
         Function<String, OptionData> nameToOption =
@@ -211,8 +216,9 @@ public void onSelectionMenu(@NotNull SelectMenuInteractionEvent event,
      * @return all options with the given prefix
      */
     @Unmodifiable
-    protected static @NotNull List<OptionMapping> getMultipleOptionsByNamePrefix(
-            @NotNull CommandInteractionPayload event, @NotNull String namePrefix) {
+    @Nonnull
+    protected static List<OptionMapping> getMultipleOptionsByNamePrefix(
+            CommandInteractionPayload event, String namePrefix) {
         return event.getOptions()
             .stream()
             .filter(option -> option.getName().startsWith(namePrefix))