Using MainActivity function inside of service is giving error why?

Question

I'm new in android. I need to use MainActivity function in service to reach service's onstartcommand again

What I expect is first service will run because of on create method but because of action is not "ACTION_PLAY" service will run MainActivity.start() function then service start again and I get println("action play working")

class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val intent = Intent(this,myService::class.java)
    intent.putExtra("action","ACTION_STOP")
    startService(intent)

}

fun start(){
    val intent = Intent(this,myService::class.java)
    intent.putExtra("action","ACTION_PLAY")
    startService(intent)
}

}

class myService: Service() {
override fun onBind(intent: Intent?): IBinder? {
    return null
}

override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {

    val action = intent?.getStringExtra("action")
    if (action == "ACTION_PLAY"){
        println("action play working")
    }
    else{
        MainActivity().start()
    }



    return super.onStartCommand(intent, flags, startId)
}

}

But it gives me this error

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.isililkproje, PID: 9526
java.lang.RuntimeException: Unable to start service com.example.isililkproje.myService@95959e6 with Intent { cmp=com.example.isililkproje/.myService (has extras) }: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
    at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3314)
    at android.app.ActivityThread.-wrap21(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1565)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6077)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
    at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:106)
    at com.example.isililkproje.MainActivity.start(MainActivity.kt:28)
    at com.example.isililkproje.myService.onStartCommand(myService.kt:19)
    at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3297)
    at android.app.ActivityThread.-wrap21(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1565) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:154) 
    at android.app.ActivityThread.main(ActivityThread.java:6077) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756) 

Please give me an explanation about this why it's giving error and how can I solve this thank you