Return immutable lists when documented

src/main/java/net/dv8tion/jda/api/entities/Guild.java

@@ -904,7 +904,7 @@ default ImageProxy getBanner()
      * <p>This will only check cached members!
      * <br>See {@link net.dv8tion.jda.api.utils.MemberCachePolicy MemberCachePolicy}
      *
-     * @return Possibly-immutable list of members who boost this guild
+     * @return Immutable list of members who boost this guild
      */
     @Nonnull
     List<Member> getBoosters();

src/main/java/net/dv8tion/jda/api/entities/Message.java

@@ -60,6 +60,7 @@
 import net.dv8tion.jda.internal.entities.ReceivedMessage;
 import net.dv8tion.jda.internal.requests.FunctionalCallback;
 import net.dv8tion.jda.internal.utils.Checks;
+import net.dv8tion.jda.internal.utils.Helpers;
 import net.dv8tion.jda.internal.utils.IOUtil;
 import okhttp3.MultipartBody;
 import okhttp3.OkHttpClient;
@@ -698,7 +699,7 @@ default List<ActionRow> getActionRows()
                 .stream()
                 .filter(ActionRow.class::isInstance)
                 .map(ActionRow.class::cast)
-                .collect(Collectors.toList());
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**
@@ -714,7 +715,7 @@ default List<Button> getButtons()
         return getComponents().stream()
                 .map(LayoutComponent::getButtons)
                 .flatMap(List::stream)
-                .collect(Collectors.toList());
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**
@@ -765,7 +766,7 @@ default List<Button> getButtonsByLabel(@Nonnull String label, boolean ignoreCase
             filter = b -> label.equals(b.getLabel());
         return getButtons().stream()
                 .filter(filter)
-                .collect(Collectors.toList());
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**

src/main/java/net/dv8tion/jda/api/entities/StageInstance.java

@@ -21,12 +21,11 @@
 import net.dv8tion.jda.api.entities.channel.concrete.StageChannel;
 import net.dv8tion.jda.api.managers.StageInstanceManager;
 import net.dv8tion.jda.api.requests.RestAction;
+import net.dv8tion.jda.internal.utils.Helpers;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nonnull;
-import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /**
  * A Stage Instance holds information about a live stage.
@@ -77,15 +76,15 @@ public interface StageInstance extends ISnowflake
      * <p>Only {@link StageChannel#isModerator(Member) stage moderators} can promote or invite speakers.
      * A stage moderator can move between speaker and audience at any time.
      *
-     * @return {@link List} of {@link Member Members} which can speak in this stage instance
+     * @return Immutable {@link List} of {@link Member Members} which can speak in this stage instance
      */
     @Nonnull
     default List<Member> getSpeakers()
     {
-        return Collections.unmodifiableList(getChannel().getMembers()
+        return getChannel().getMembers()
                 .stream()
                 .filter(member -> !member.getVoiceState().isSuppressed()) // voice states should not be null since getMembers() checks only for connected members in the channel
-                .collect(Collectors.toList()));
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**
@@ -98,15 +97,15 @@ default List<Member> getSpeakers()
      * <p>Only {@link StageChannel#isModerator(Member) stage moderators} can promote or invite speakers.
      * A stage moderator can move between speaker and audience at any time.
      *
-     * @return {@link List} of {@link Member Members} which cannot speak in this stage instance
+     * @return Immutable {@link List} of {@link Member Members} which cannot speak in this stage instance
      */
     @Nonnull
     default List<Member> getAudience()
     {
-        return Collections.unmodifiableList(getChannel().getMembers()
+        return getChannel().getMembers()
                 .stream()
                 .filter(member -> member.getVoiceState().isSuppressed()) // voice states should not be null since getMembers() checks only for connected members in the channel
-                .collect(Collectors.toList()));
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**

src/main/java/net/dv8tion/jda/api/entities/channel/attribute/IPermissionContainer.java

@@ -21,13 +21,12 @@
 import net.dv8tion.jda.api.entities.channel.middleman.GuildChannel;
 import net.dv8tion.jda.api.managers.channel.attribute.IPermissionContainerManager;
 import net.dv8tion.jda.api.requests.restaction.PermissionOverrideAction;
+import net.dv8tion.jda.internal.utils.Helpers;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /**
  * Represents a {@link GuildChannel} that uses {@link net.dv8tion.jda.api.entities.PermissionOverride Permission Overrides}.
@@ -89,9 +88,9 @@ public interface IPermissionContainer extends GuildChannel
     @Nonnull
     default List<PermissionOverride> getMemberPermissionOverrides()
     {
-        return Collections.unmodifiableList(getPermissionOverrides().stream()
+        return getPermissionOverrides().stream()
                 .filter(PermissionOverride::isMemberOverride)
-                .collect(Collectors.toList()));
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**
@@ -105,9 +104,9 @@ default List<PermissionOverride> getMemberPermissionOverrides()
     @Nonnull
     default List<PermissionOverride> getRolePermissionOverrides()
     {
-        return Collections.unmodifiableList(getPermissionOverrides().stream()
+        return getPermissionOverrides().stream()
                 .filter(PermissionOverride::isRoleOverride)
-                .collect(Collectors.toList()));
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**

src/main/java/net/dv8tion/jda/api/entities/channel/attribute/IThreadContainer.java

@@ -26,12 +26,11 @@
 import net.dv8tion.jda.api.requests.restaction.pagination.ThreadChannelPaginationAction;
 import net.dv8tion.jda.api.utils.MiscUtil;
 import net.dv8tion.jda.api.utils.messages.MessageCreateData;
+import net.dv8tion.jda.internal.utils.Helpers;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nonnull;
-import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /**
  * Abstraction of all channel types, which can contain or manage {@link ThreadChannel ThreadChannels}.
@@ -59,11 +58,10 @@ public interface IThreadContainer extends GuildChannel, IPermissionContainer
     @Nonnull
     default List<ThreadChannel> getThreadChannels()
     {
-        return Collections.unmodifiableList(
-            getGuild().getThreadChannelCache().applyStream(stream ->
-                stream.filter(thread -> thread.getParentChannel() == this)
-                      .collect(Collectors.toList())
-            ));
+        return getGuild().getThreadChannelCache().applyStream(stream ->
+            stream.filter(thread -> thread.getParentChannel() == this)
+                  .collect(Helpers.toUnmodifiableList())
+        );
     }
 
     /**

src/main/java/net/dv8tion/jda/api/entities/channel/concrete/Category.java

@@ -32,9 +32,7 @@
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nonnull;
-import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /**
  * Represents a channel category in the official Discord API.
@@ -80,11 +78,11 @@ default List<GuildChannel> getChannels()
     @Nonnull
     default List<TextChannel> getTextChannels()
     {
-        return Collections.unmodifiableList(getGuild().getTextChannelCache().applyStream(stream ->
+        return getGuild().getTextChannelCache().applyStream(stream ->
             stream.filter(channel -> equals(channel.getParentCategory()))
                   .sorted()
-                  .collect(Collectors.toList())
-        ));
+                  .collect(Helpers.toUnmodifiableList())
+        );
     }
 
     /**
@@ -96,11 +94,11 @@ default List<TextChannel> getTextChannels()
     @Nonnull
     default List<NewsChannel> getNewsChannels()
     {
-        return Collections.unmodifiableList(getGuild().getNewsChannelCache().applyStream(stream ->
+        return getGuild().getNewsChannelCache().applyStream(stream ->
             stream.filter(channel -> equals(channel.getParentCategory()))
                   .sorted()
-                  .collect(Collectors.toList())
-        ));
+                  .collect(Helpers.toUnmodifiableList())
+        );
     }
 
     /**
@@ -111,11 +109,11 @@ default List<NewsChannel> getNewsChannels()
     @Nonnull
     default List<ForumChannel> getForumChannels()
     {
-        return Collections.unmodifiableList(getGuild().getForumChannelCache().applyStream(stream ->
+        return getGuild().getForumChannelCache().applyStream(stream ->
             stream.filter(channel -> equals(channel.getParentCategory()))
                   .sorted()
-                  .collect(Collectors.toList())
-        ));
+                  .collect(Helpers.toUnmodifiableList())
+        );
     }
 
     /**
@@ -126,11 +124,11 @@ default List<ForumChannel> getForumChannels()
     @Nonnull
     default List<MediaChannel> getMediaChannels()
     {
-        return Collections.unmodifiableList(getGuild().getMediaChannelCache().applyStream(stream ->
+        return getGuild().getMediaChannelCache().applyStream(stream ->
                 stream.filter(channel -> equals(channel.getParentCategory()))
                         .sorted()
-                        .collect(Collectors.toList())
-        ));
+                        .collect(Helpers.toUnmodifiableList())
+        );
     }
 
     /**
@@ -142,11 +140,11 @@ default List<MediaChannel> getMediaChannels()
     @Nonnull
     default List<VoiceChannel> getVoiceChannels()
     {
-        return Collections.unmodifiableList(getGuild().getVoiceChannelCache().applyStream(stream ->
+        return getGuild().getVoiceChannelCache().applyStream(stream ->
             stream.filter(channel -> equals(channel.getParentCategory()))
                   .sorted()
-                  .collect(Collectors.toList())
-        ));
+                  .collect(Helpers.toUnmodifiableList())
+        );
     }
 
     /**
@@ -158,11 +156,11 @@ default List<VoiceChannel> getVoiceChannels()
     @Nonnull
     default List<StageChannel> getStageChannels()
     {
-        return Collections.unmodifiableList(getGuild().getStageChannelCache().applyStream(stream ->
+        return getGuild().getStageChannelCache().applyStream(stream ->
             stream.filter(channel -> equals(channel.getParentCategory()))
                   .sorted()
-                  .collect(Collectors.toList())
-        ));
+                  .collect(Helpers.toUnmodifiableList())
+        );
     }
 
     /**
@@ -447,13 +445,13 @@ default List<StageChannel> getStageChannels()
     @Override
     default List<Member> getMembers()
     {
-        return Collections.unmodifiableList(getChannels().stream()
+        return getChannels().stream()
             .filter(IMemberContainer.class::isInstance)
             .map(IMemberContainer.class::cast)
             .map(IMemberContainer::getMembers)
             .flatMap(List::stream)
             .distinct()
-            .collect(Collectors.toList()));
+            .collect(Helpers.toUnmodifiableList());
     }
 
     @Nonnull

src/main/java/net/dv8tion/jda/api/interactions/components/LayoutComponent.java

@@ -20,6 +20,7 @@
 import net.dv8tion.jda.api.interactions.components.buttons.ButtonStyle;
 import net.dv8tion.jda.api.utils.data.SerializableData;
 import net.dv8tion.jda.internal.utils.Checks;
+import net.dv8tion.jda.internal.utils.Helpers;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nonnull;
@@ -74,7 +75,7 @@ default List<ActionComponent> getActionComponents()
         return getComponents().stream()
                 .filter(ActionComponent.class::isInstance)
                 .map(ActionComponent.class::cast)
-                .collect(Collectors.toList());
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**
@@ -85,11 +86,10 @@ default List<ActionComponent> getActionComponents()
     @Nonnull
     default List<Button> getButtons()
     {
-        return Collections.unmodifiableList(
-            getComponents().stream()
+        return getComponents().stream()
                 .filter(Button.class::isInstance)
                 .map(Button.class::cast)
-                    .collect(Collectors.toList()));
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**

src/main/java/net/dv8tion/jda/api/interactions/components/selections/StringSelectInteraction.java

@@ -17,10 +17,10 @@
 package net.dv8tion.jda.api.interactions.components.selections;
 
 import net.dv8tion.jda.api.events.interaction.component.StringSelectInteractionEvent;
+import net.dv8tion.jda.internal.utils.Helpers;
 
 import javax.annotation.Nonnull;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /**
  * Component Interaction for a {@link StringSelectMenu}.
@@ -42,7 +42,7 @@ public interface StringSelectInteraction extends SelectMenuInteraction<String, S
      * This resolves the selected {@link #getValues() values} to the representative {@link SelectOption SelectOption} instances.
      * <br>It is recommended to check {@link #getValues()} directly instead of using the options.
      *
-     * @return {@link List} of the selected options
+     * @return Immutable {@link List} of the selected options
      */
     @Nonnull
     default List<SelectOption> getSelectedOptions()
@@ -52,6 +52,6 @@ default List<SelectOption> getSelectedOptions()
         return menu.getOptions()
                 .stream()
                 .filter(it -> values.contains(it.getValue()))
-                .collect(Collectors.toList());
+                .collect(Helpers.toUnmodifiableList());
     }
 }

src/main/java/net/dv8tion/jda/api/sharding/ShardManager.java

@@ -39,6 +39,7 @@
 import net.dv8tion.jda.internal.requests.CompletedRestAction;
 import net.dv8tion.jda.internal.requests.RestActionImpl;
 import net.dv8tion.jda.internal.utils.Checks;
+import net.dv8tion.jda.internal.utils.Helpers;
 import net.dv8tion.jda.internal.utils.cache.UnifiedChannelCacheView;
 
 import javax.annotation.CheckReturnValue;
@@ -428,11 +429,10 @@ default List<Guild> getGuilds()
     default List<Guild> getMutualGuilds(@Nonnull final Collection<User> users)
     {
         Checks.noneNull(users, "users");
-        return Collections.unmodifiableList(
-                this.getGuildCache().stream()
+        return this.getGuildCache().stream()
                 .filter(guild -> users.stream()
                         .allMatch(guild::isMember))
-                .collect(Collectors.toList()));
+                .collect(Helpers.toUnmodifiableList());
     }
 
     /**

src/main/java/net/dv8tion/jda/api/utils/messages/MessageEditData.java

@@ -25,11 +25,11 @@
 import net.dv8tion.jda.api.utils.data.DataArray;
 import net.dv8tion.jda.api.utils.data.DataObject;
 import net.dv8tion.jda.api.utils.data.SerializableData;
+import net.dv8tion.jda.internal.utils.Helpers;
 import net.dv8tion.jda.internal.utils.IOUtil;
 
 import javax.annotation.Nonnull;
 import java.util.*;
-import java.util.stream.Collectors;
 
 import static net.dv8tion.jda.api.utils.messages.MessageEditBuilder.*;
 
@@ -351,12 +351,10 @@ public synchronized DataObject toData()
     @Nonnull
     public synchronized List<FileUpload> getFiles()
     {
-        return Collections.unmodifiableList(
-            files.stream()
-                 .filter(FileUpload.class::isInstance)
-                 .map(FileUpload.class::cast)
-                 .collect(Collectors.toList())
-        );
+        return files.stream()
+                .filter(FileUpload.class::isInstance)
+                .map(FileUpload.class::cast)
+                .collect(Helpers.toUnmodifiableList());
     }
 
     @Override