Multithreading

Multithreading is an object utility that provides thread pools and utilities for executing tasks asynchronously in Minecraft mods.

Accessing Multithreading

import gg.essential.api.utils.Multithreading

// Multithreading is an object, use it directly
Multithreading.runAsync {
    // Your async code here
}

import gg.essential.api.utils.Multithreading;

// Use static methods in Java
Multithreading.runAsync(() -> {
    // Your async code here
});

Thread Pools

Multithreading provides two thread pools for different use cases:

pool

General-purpose thread pool executor for running async tasks.

val executor = Multithreading.pool

// Direct access to ThreadPoolExecutor
executor.execute {
    println("Running in thread: ${Thread.currentThread().name}")
}

Configuration:

Core pool size: 10 threads
Maximum pool size: 30 threads
Keep-alive time: 0 seconds
Queue: LinkedBlockingQueue (unbounded)
Thread naming: “Thread 1”, “Thread 2”, etc.

scheduledPool

Scheduled executor service for delayed and repeating tasks.

val scheduler = Multithreading.scheduledPool

// Direct access to ScheduledExecutorService
scheduler.schedule({ println("Delayed task") }, 5, TimeUnit.SECONDS)

Configuration:

Pool size: 10 threads
Thread naming: “Thread 1”, “Thread 2”, etc.

Running Async Tasks

runAsync

Execute a task asynchronously on the thread pool.

Kotlin
Java

import gg.essential.api.utils.Multithreading

Multithreading.runAsync {
    // This runs on a background thread
    val data = fetchDataFromApi()
    println("Fetched: $data")
}

import gg.essential.api.utils.Multithreading;

Multithreading.runAsync(() -> {
    // This runs on a background thread
    String data = fetchDataFromApi();
    System.out.println("Fetched: " + data);
});

Parameters:

runnable: Runnable - The task to execute

Notes:

Tasks execute immediately (no delay)
Uses the general-purpose thread pool
Non-blocking operation

submit

Submit a task and receive a Future to track completion.

import java.util.concurrent.Future

val future: Future<*> = Multithreading.submit {
    // Long-running task
    Thread.sleep(5000)
    println("Task completed")
}

// Check if task is done
if (future.isDone) {
    println("Task finished")
}

// Wait for task to complete
future.get()

Parameters:

runnable: Runnable - The task to submit

Returns: Future<*> - A future representing the task execution

Scheduling Tasks

schedule (Single Execution)

Schedule a task to run once after a delay.

import java.util.concurrent.TimeUnit
import java.util.concurrent.ScheduledFuture

val future: ScheduledFuture<*> = Multithreading.schedule(
    { println("Delayed task executed") },
    delay = 5,
    unit = TimeUnit.SECONDS
)

// Cancel the scheduled task if needed
future.cancel(false)

Parameters:

r: Runnable - The task to execute
delay: Long - Delay before execution
unit: TimeUnit - Time unit for the delay

Returns: ScheduledFuture<*> - A future representing the scheduled task

schedule (Repeating Execution)

Schedule a task to run repeatedly at fixed intervals.

import java.util.concurrent.TimeUnit

val repeatingTask = Multithreading.schedule(
    r = { println("Tick: ${System.currentTimeMillis()}") },
    initialDelay = 0,
    delay = 1,
    unit = TimeUnit.SECONDS
)

// Cancel after some time
Thread.sleep(5000)
repeatingTask.cancel(false)

Parameters:

r: Runnable - The task to execute repeatedly
initialDelay: Long - Delay before first execution
delay: Long - Delay between subsequent executions
unit: TimeUnit - Time unit for delays

Returns: ScheduledFuture<*> - A future representing the scheduled task Notes:

Uses fixed-rate scheduling (not fixed-delay)
Executions may overlap if task takes longer than the delay

Object Reference

object Multithreading {
    val pool: ThreadPoolExecutor
    val scheduledPool: ScheduledExecutorService
    
    fun runAsync(runnable: Runnable)
    fun submit(runnable: Runnable): Future<*>
    fun schedule(r: Runnable, delay: Long, unit: TimeUnit): ScheduledFuture<*>
    fun schedule(
        r: Runnable,
        initialDelay: Long,
        delay: Long,
        unit: TimeUnit
    ): ScheduledFuture<*>
}

Common Use Cases

Background API Requests

import gg.essential.api.utils.Multithreading
import gg.essential.api.utils.WebUtil

fun fetchPlayerData(uuid: String) {
    Multithreading.runAsync {
        // Runs off the main thread
        val json = WebUtil.fetchJSON("https://api.example.com/player/$uuid")
        val playerName = json.optString("name")
        
        // Update UI on main thread if needed
        println("Player: $playerName")
    }
}

Delayed Actions

import java.util.concurrent.TimeUnit

fun showDelayedMessage() {
    Multithreading.schedule(
        { println("This appears after 3 seconds") },
        delay = 3,
        unit = TimeUnit.SECONDS
    )
}

Periodic Tasks

import java.util.concurrent.TimeUnit
import java.util.concurrent.ScheduledFuture

class AutoSaver {
    private var saveTask: ScheduledFuture<*>? = null
    
    fun start() {
        saveTask = Multithreading.schedule(
            r = { performAutoSave() },
            initialDelay = 60,
            delay = 60,
            unit = TimeUnit.SECONDS
        )
    }
    
    fun stop() {
        saveTask?.cancel(false)
    }
    
    private fun performAutoSave() {
        println("Auto-saving...")
        // Save logic here
    }
}

Parallel Processing

import java.util.concurrent.Future

fun processMultipleItems(items: List<String>) {
    val futures = mutableListOf<Future<*>>()
    
    items.forEach { item ->
        val future = Multithreading.submit {
            processItem(item)
        }
        futures.add(future)
    }
    
    // Wait for all tasks to complete
    futures.forEach { it.get() }
    println("All items processed")
}

fun processItem(item: String) {
    println("Processing: $item")
    Thread.sleep(1000)
}

Async with Callback

fun asyncOperation(callback: (String) -> Unit) {
    Multithreading.runAsync {
        // Simulate long operation
        Thread.sleep(2000)
        val result = "Operation complete"
        
        // Invoke callback with result
        callback(result)
    }
}

// Usage
asyncOperation { result ->
    println("Result: $result")
}

Timeout Handling

import java.util.concurrent.TimeUnit
import java.util.concurrent.TimeoutException

fun operationWithTimeout() {
    val future = Multithreading.submit {
        // Potentially long-running task
        Thread.sleep(10000)
        "Done"
    }
    
    try {
        // Wait max 5 seconds
        future.get(5, TimeUnit.SECONDS)
        println("Operation completed in time")
    } catch (e: TimeoutException) {
        println("Operation timed out")
        future.cancel(true)
    }
}

Debounced Actions

import java.util.concurrent.ScheduledFuture
import java.util.concurrent.TimeUnit

class DebouncedAction(private val delayMs: Long, private val action: () -> Unit) {
    private var scheduledTask: ScheduledFuture<*>? = null
    
    fun trigger() {
        // Cancel previous scheduled execution
        scheduledTask?.cancel(false)
        
        // Schedule new execution
        scheduledTask = Multithreading.schedule(
            action,
            delayMs,
            TimeUnit.MILLISECONDS
        )
    }
}

// Usage
val debouncedSave = DebouncedAction(1000) {
    println("Saving...")
    saveConfig()
}

// Each call resets the timer
debouncedSave.trigger()
debouncedSave.trigger()  // Previous call is cancelled
debouncedSave.trigger()  // Only this one will execute after 1s

Thread-Safe GUI Updates

import gg.essential.api.utils.GuiUtil

fun loadDataAndUpdateGui() {
    Multithreading.runAsync {
        // Load data in background
        val data = loadHeavyData()
        
        // Update GUI on main thread
        GuiUtil.open(ResultsScreen(data))
    }
}

Best Practices

Don’t block the main thread: Use runAsync for I/O operations, network requests, or heavy computations
Handle exceptions: Wrap async code in try-catch blocks to prevent silent failures

Multithreading.runAsync {
    try {
        riskyOperation()
    } catch (e: Exception) {
        println("Error: ${e.message}")
    }
}

Clean up scheduled tasks: Cancel repeating tasks when no longer needed

class MyMod {
    private var updateTask: ScheduledFuture<*>? = null
    
    fun onEnable() {
        updateTask = Multithreading.schedule(::update, 0, 20, TimeUnit.SECONDS)
    }
    
    fun onDisable() {
        updateTask?.cancel(false)
    }
    
    fun update() {
        // Periodic update logic
    }
}

Use appropriate time units: Choose the most readable unit for your delays

// Good - clear and readable
Multithreading.schedule(task, 5, TimeUnit.MINUTES)

// Less clear
Multithreading.schedule(task, 300, TimeUnit.SECONDS)

Notes

Thread pools are shared across the application - avoid blocking operations
Scheduled tasks use fixed-rate execution, not fixed-delay
All threads are named sequentially: “Thread 1”, “Thread 2”, etc.
The general pool can grow to 30 threads maximum
Tasks are queued if all threads are busy
Always handle exceptions in async code to prevent thread pool contamination

Getting Started

Core API

Commands

GUI

Utilities

Other APIs

Accessing Multithreading

Thread Pools

pool

scheduledPool

Running Async Tasks

runAsync

submit

Scheduling Tasks

schedule (Single Execution)

schedule (Repeating Execution)

Object Reference

Common Use Cases

Background API Requests

Delayed Actions

Periodic Tasks

Parallel Processing

Async with Callback

Timeout Handling

Debounced Actions

Thread-Safe GUI Updates

Best Practices

Notes

Build docs developers (and LLMs) love

Getting Started

Core API

Commands

GUI

Utilities

Other APIs

​Accessing Multithreading

​Thread Pools

​pool

​scheduledPool

​Running Async Tasks

​runAsync

​submit

​Scheduling Tasks

​schedule (Single Execution)

​schedule (Repeating Execution)

​Object Reference

​Common Use Cases

​Background API Requests

​Delayed Actions

​Periodic Tasks

​Parallel Processing

​Async with Callback

​Timeout Handling

​Debounced Actions

​Thread-Safe GUI Updates

​Best Practices

​Notes

Build docs developers (and LLMs) love

Accessing Multithreading

Thread Pools

pool

scheduledPool

Running Async Tasks

runAsync

submit

Scheduling Tasks

schedule (Single Execution)

schedule (Repeating Execution)

Object Reference

Common Use Cases

Background API Requests

Delayed Actions

Periodic Tasks

Parallel Processing

Async with Callback

Timeout Handling

Debounced Actions

Thread-Safe GUI Updates

Best Practices

Notes