Bound service leaks memory

Question

I wrote a basic bound service based on the Android documentation, but LeakCanary is telling me the service is leaking.

1. Is there a leak or have I misconfigured LeakCanary?
2. How can I write a bound service that does not leak?

The Code

class LocalService : Service() {

  private val binder = LocalBinder()
  private val generator = Random()

  val randomNumber: Int
    get() = generator.nextInt(100)

  inner class LocalBinder : Binder() {
    fun getService(): LocalService = this@LocalService
  }

  override fun onBind(intent: Intent): IBinder {
    return binder
  }

  override fun onDestroy() {
    super.onDestroy()
    LeakSentry.refWatcher.watch(this) // Only modification is to add LeakCanary
  }
}

If I bind to the service from an activity as follows, LeakCanary detects the service has leaked

class MainActivity: Activity() {

  private var service: LocalService? = null
  private val serviceConnection = object: ServiceConnection {
    override fun onServiceConnected(name: ComponentName?, binder: IBinder?) {
      service = (binder as LocalBinder).getService()
    }
    override fun onServiceDisconnected(name: ComponentName?) {
      service = null
    }
  }

  override fun onStart() {
    super.onStart()
    bindService(Intent(this, LocalService::class.java), serviceConnection, BIND_AUTO_CREATE)
  } 

  override fun onStop() {
    super.onStop()
    service?.let {
      unbindService(serviceConnection)
      service = null
    }
  }
}

┬
├─ com.example.serviceleak.LocalService$LocalBinder
│    Leaking: NO (it's a GC root)
│    ↓ LocalService$LocalBinder.this$0
│                               ~~~~~~
╰→ com.example.serviceleak.LocalService
​     Leaking: YES (RefWatcher was watching this)

Answer 1

I don't know if it's late to answer but after reading your question I also setup leakCanary in my project and found this leak. I was sure that it's because of the inner binder class which is holding the reference of outer class which is service here. That is why in your leak log it shows LocationService is leaking. I found a solution by @commonsguy here and implemented the solution with a bit simpler example here. Hope this helps. Keep coding, stay blessed.