org.bukkit.command.CommandException: Unhandled exception executing command 'attributes' in plugin AttributeBug v1.0
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[spigot-api-1.21.1-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:150) ~[spigot-api-1.21.1-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.craftbukkit.v1_21_R1.CraftServer.dispatchCommand(CraftServer.java:921) ~[spigot-1.21.1-R0.1-SNAPSHOT.jar:4300-Spigot-a759b62-7070de8]
        at org.bukkit.craftbukkit.v1_21_R1.CraftServer.dispatchServerCommand(CraftServer.java:906) ~[spigot-1.21.1-R0.1-SNAPSHOT.jar:4300-Spigot-a759b62-7070de8]
        at net.minecraft.server.dedicated.DedicatedServer.br(DedicatedServer.java:431) ~[spigot-1.21.1-R0.1-SNAPSHOT.jar:4300-Spigot-a759b62-7070de8]
        at net.minecraft.server.dedicated.DedicatedServer.c(DedicatedServer.java:407) ~[spigot-1.21.1-R0.1-SNAPSHOT.jar:4300-Spigot-a759b62-7070de8]
        at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:1321) ~[spigot-1.21.1-R0.1-SNAPSHOT.jar:4300-Spigot-a759b62-7070de8]
        at net.minecraft.server.MinecraftServer.y(MinecraftServer.java:1071) ~[spigot-1.21.1-R0.1-SNAPSHOT.jar:4300-Spigot-a759b62-7070de8]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:318) ~[spigot-1.21.1-R0.1-SNAPSHOT.jar:4300-Spigot-a759b62-7070de8]
        at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]
Caused by: java.lang.IllegalArgumentException: Invalid UUID string: minecraft:base_attack_damage
        at java.base/java.util.UUID.fromString1(UUID.java:282) ~[?:?]
        at java.base/java.util.UUID.fromString(UUID.java:260) ~[?:?]
        at org.bukkit.attribute.AttributeModifier.getUniqueId(AttributeModifier.java:68) ~[spigot-api-1.21.1-R0.1-SNAPSHOT.jar:?]
        at java.base/java.lang.Iterable.forEach(Iterable.java:75) ~[?:?]
        at nl.knokko.attribute.AttributePlugin.onCommand(AttributePlugin.java:23) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[spigot-api-1.21.1-R0.1-SNAPSHOT.jar:?]
        ... 9 more 

@SuppressWarnings("unused")
public class AttributePlugin extends JavaPlugin {

    @Override
    public void onEnable() {
       getCommand("attributes").setExecutor(this);
    }

    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
       var attributes = Material.IRON_SWORD.getDefaultAttributeModifiers(EquipmentSlot.HAND);

       //noinspection ResultOfMethodCallIgnored
       attributes.values().forEach(AttributeModifier::getUniqueId);
       sender.sendMessage("Success! There were " + attributes.size() + " attributes");

       return true;
    }
}