Need help figuring out this Java class | latcord | Page 1

errant sorrel Jan 27, 2026, 5:13 PM

#

As far as I can tell, you cant summon the Species spectrte mobs tamed, even with the owner tag, so ive resorted to reading the source code to find the trigger event for the tamed spawning

Ive gotten so very close, but I cant figure out what to input for the 3rd var in the spawnSpectre event

const Spectre = Java.loadClass("com.ninni.species.server.entity.mob.update_3.Spectre")
const ServerLevel = Java.loadClass("net.minecraft.server.level.ServerLevel")

ForgeEvents.onEvent("net.minecraftforge.event.entity.living.MobEffectEvent$Expired", event => global.effectsSpectralibur(event));
/**
 * 
 * @param {Internal.MobEffectEvent$Expired} event 
 */
global.effectsSpectralibur = event => {
    const { effectInstance, effectInstance: { descriptionId }, entity, player, ServerLevel} = event
    console.log(descriptionId, effectInstance.amplifier)
    try {
        if (descriptionId == "effect.weapon_class.stealth" && effectInstance.amplifier > -1 && entity.mainHandItem === 'species:spectralibur') {
            entity.server.scheduleInTicks(10, () => {
              Spectre.spawnSpectre(ServerLevel, player, player.getOnPos(), Spectre.Type.SPECTRE, true)
              Utils.server.runCommandSilent(`say it problably worked...`)
            }
          )
        }
    } catch (error) {
        console.log(error)
    }
}

sorce code for the mod here: https://github.com/Peculiar-Room/Species/blob/main/src/main/java/com/ninni/species/server/item/SpectraliburItem.java

returns [Server thread/ERROR] [KubeJS Server/]: startup_scripts:weapon_class/spectralibur.js#15: Error occurred while handling scheduled event callback: TypeError: Cannot call method "getOnPos" of undefined on effect end

any help is greatly appreciated

crisp dockBOT Jan 27, 2026, 5:13 PM

#

Once your ticket has been resolved, please close it with </ticket close:1054771505520717835> command!

errant sorrel Jan 27, 2026, 5:14 PM

#

It would be so nice if the mod wasn't hard coded to just not let you spawn the mob as a tamed pet

#

If any more information is needed, please let me know so I can provide it

errant sorrel Jan 27, 2026, 8:36 PM

#

it has only been 3 hours but ima bump this anyway

last pagoda Jan 27, 2026, 9:45 PM

#

Neither player nor ServerLevel exist in event, so both are undefined

#

I really wonder, why are you setting your event in global?

errant sorrel Jan 27, 2026, 9:50 PM

#

last pagoda I really wonder, why are you setting your event in `global`?

O that's cuz I'm not smart

#

This is the result of me just throwing things at the wall untill it stops giving me errors

#

Both ServerLevel and player where comming out as empty at first but it seems to have stopped doing that nor did it causes a crash when they where defined

last pagoda Jan 28, 2026, 9:26 AM

#

Ok, but that doesn't change the fact that player and ServerLevel are not present in event object

errant sorrel Jan 28, 2026, 9:33 AM

#

Makes sense

#

But how would I add em?

last pagoda Jan 28, 2026, 9:36 AM

#

You can't

#

Remove ServerLevel from the destructuring pattern

#

So that ServerLevel variable will be visible (due to being in scope)

errant sorrel Jan 28, 2026, 7:51 PM

#

last pagoda So that `ServerLevel` variable will be visible (due to being in scope)

O shit it's green now

#

Or teal

#

this color

const Spectre = Java.loadClass("com.ninni.species.server.entity.mob.update_3.Spectre")
const ServerLevel = Java.loadClass("net.minecraft.server.level.ServerLevel")

ForgeEvents.onEvent("net.minecraftforge.event.entity.living.MobEffectEvent$Expired", event => global.effectsSpectralibur(event));
/**
 * 
 * @param {Internal.MobEffectEvent$Expired} event 
 */
global.effectsSpectralibur = event => {
    const { effectInstance, effectInstance: { descriptionId }, entity, player} = event
    console.log(descriptionId, effectInstance.amplifier)
    try {
        if (descriptionId == "effect.weapon_class.stealth" && effectInstance.amplifier > -1 && entity.mainHandItem === 'species:spectralibur') {
            entity.server.scheduleInTicks(10, () => {
              Spectre.spawnSpectre(ServerLevel, player, player.getOnPos(), Spectre.Type.SPECTRE, true)
              Utils.server.runCommandSilent(`say it problably worked...`)
            }
          )
        }
    } catch (error) {
        console.log(error)
    }
}

#

o wait that dosent work

#

Teal

last pagoda Jan 28, 2026, 7:53 PM

#

You are still trying to destructure player from event which is undefined

#

Also, what are you trying to do with the ServerLevel?

#

Oh, you want a dimension

#

But ServerLevel is a class reference, not an instance

#

One thing I can tell you immediately, this won't be needed

errant sorrel Jan 28, 2026, 7:54 PM

#

I see

last pagoda Jan 28, 2026, 7:54 PM

#

You should get level from the entity

errant sorrel Jan 28, 2026, 7:55 PM

#

last pagoda You should get level from the entity

easy enough

global.effectsSpectralibur = event => {
    const { effectInstance, effectInstance: { descriptionId }, entity} = event
    console.log(descriptionId, effectInstance.amplifier)
    try {
        if (descriptionId == "effect.weapon_class.stealth" && effectInstance.amplifier > -1 && entity.mainHandItem === 'species:spectralibur') {
            entity.server.scheduleInTicks(10, () => {
              Spectre.spawnSpectre(entity.level.dimension, player, player.getOnPos(), Spectre.Type.SPECTRE, true)
              Utils.server.runCommandSilent(`say it problably worked...`)
            }
          )
        }
    } catch (error) {
        console.log(error)
    }
}

last pagoda Jan 28, 2026, 7:55 PM

#

const Spectre = Java.loadClass('com.ninni.species.server.entity.mob.update_3.Spectre')
const $MobEffectEventExpired = Java.loadClass('net.minecraftforge.event.entity.living.MobEffectEvent$Expired')

ForgeEvents.onEvent($MobEffectEventExpired, event => {
  const { effectInstance, entity } = event
  const { descriptionId } = effectInstance
  console.log(descriptionId, effectInstance.amplifier)
  if (entity.isPlayer())
    if (
      descriptionId == 'effect.weapon_class.stealth' &&
      effectInstance.amplifier > -1 &&
      entity.mainHandItem === 'species:spectralibur'
    ) {
      entity.server.scheduleInTicks(10, () => {
        Spectre.spawnSpectre(entity.level, entity, entity.getOnPos(), Spectre.Type.SPECTRE, true)
        Utils.server.runCommandSilent(`say it problably worked...`)
      })
    }
})

errant sorrel Jan 28, 2026, 7:55 PM

#

99% sure this is how that's fone

#

Donw

#

Done

#

GOD

last pagoda Jan 28, 2026, 7:56 PM

#

level.dimension is a ResourceLocation, not a ServerLevel.

#

Maybe there's a type wrapper (as usual with KubeJS), it there is I'll be surprised

errant sorrel Jan 28, 2026, 7:57 PM

#

last pagoda `level.dimension` is a `ResourceLocation`, not a `ServerLevel`.

is that why it works in in line commands I right but not functions?

#

Or

#

Most functions anyway

last pagoda Jan 28, 2026, 7:57 PM

#

What do you mean by "inline commands"?

#

level.dimension is a "bean" - which is equivalent to level.getDimension()

errant sorrel Jan 28, 2026, 7:58 PM

#

Utils.server.runcommandsilent

errant sorrel Jan 28, 2026, 7:58 PM

#

last pagoda `level.dimension` is a "bean" - which is equivalent to `level.getDimension()`

I sees

last pagoda Jan 28, 2026, 7:58 PM

#

You should get the server from the entity as well

#

Or even better - don't use commands

#

ForgeEvents.onEvent($MobEffectEventExpired, event => {
  const { effectInstance, entity } = event
  const { descriptionId } = effectInstance
  const server = entity.server
  console.log(descriptionId, effectInstance.amplifier)
  if (entity.isPlayer())
    if (
      descriptionId == 'effect.weapon_class.stealth' &&
      effectInstance.amplifier > -1 &&
      entity.mainHandItem === 'species:spectralibur'
    ) {
      entity.server.scheduleInTicks(10, () => {
        Spectre.spawnSpectre(entity.level, entity, entity.getOnPos(), Spectre.Type.SPECTRE, true)
        server.tell('it problably worked...')
      })
    }
})

last pagoda Jan 28, 2026, 7:59 PM

#

errant sorrel is that why it works in in line commands I right but not functions?

Yes

#

ResourceLocation will be converted quite straightforwardly to string

#

But not ServerLevel

errant sorrel Jan 28, 2026, 8:00 PM

#

Yeah that makes sense!

#

Seems kinda dumb but i'm guessing that's just a result of something like "IDs are handled differently than strings"

last pagoda Jan 28, 2026, 8:01 PM

#

No

#

All non-string objects are handled differently from strings

#

If you pass an object in a place that expects a string, the object's toString() method is invoked

errant sorrel Jan 28, 2026, 8:02 PM

#

I mean I know that

last pagoda Jan 28, 2026, 8:02 PM

#

And object conversion to string will differ from object to object

errant sorrel Jan 28, 2026, 8:03 PM

#

Aaaaaaaaah

#

Ok that makes sense

last pagoda Jan 28, 2026, 8:03 PM

#

Each class can specify its own behavior of toString

errant sorrel Jan 28, 2026, 8:03 PM

#

last pagoda Each class can specify its own behavior of `toString`

Anyway I can see that outside of log files?

#

Sorry if I'm asking too many questions

#

You're just explaining things to me in a way that makes a lot of sense

last pagoda Jan 28, 2026, 8:04 PM

#

errant sorrel Sorry if I'm asking too many questions

If you are asking questions, that's great

errant sorrel Jan 28, 2026, 8:04 PM

#

Which thank you

errant sorrel Jan 28, 2026, 8:04 PM

#

last pagoda If you are asking questions, that's great

You are the coolest person here

#

My dad purchased a Java crash course for himself but I'm gonna take that too in your honor

#

And it works perfectly now!

#

Thank you so so much

last pagoda Jan 28, 2026, 8:06 PM

#

errant sorrel Anyway I can see that outside of log files?

For example, ResourceLocation's toString is very straightforward:

public String toString() {
    return this.namespace + ":" + this.path;
}

errant sorrel Jan 28, 2026, 8:06 PM

#

You have been a huge help

errant sorrel Jan 28, 2026, 8:07 PM

#

last pagoda For example, `ResourceLocation`'s `toString` is very straightforward: ```java pu...

It is, and it is very funny to me for some reason

last pagoda Jan 28, 2026, 8:07 PM

#

But ServerLevel's toString is generic, and helps one learn that this is indeed a ServerLevel

public String toString() {
    return "ServerLevel[" + this.serverLevelData.getLevelName() + "]";
}

#

You can read vanilla source code by:

Opening up IntelliJ IDEA
Downloading the "Minecraft Development" plugin (just to make creating mod dev environments easier)
Creating a 1.20.1 Forge mod dev env
Wating for Gradle to do its job

errant sorrel Jan 28, 2026, 8:09 PM

#

Understood

#

I'm gonna try and do that tonight

#

Again, thank you for your help

#Need help figuring out this Java class