How to initialize an Android timer code

Android Timers.java

final Handler handler = new Handler(); // A handler is a way used to run the code every certain delayed time
Runnable run  = new Runnable (){ // A Runnable is the that code
  @Override 
   public void run (){ // An override fuction describe exactly the action to be taken within that time
     
     //Insert a code to be run every certain "delayed time" 
     
     handler.postDelayed (this, 1000); // initialize the handler delayer for 1000msec= 1 second 
   }
   
   handler.post(run); // handler initializer 
}

//////////////////////////////////////////////////////////////////////////
//////////////////// Another Timer Method////////////////////////////////
////////////////////////////////////////////////////////////////////////

new CountDownTimer = (10000, 1000){ // to take the initial time and the frequency of decreasing 
public void onTick(long milliSecondsUntilDone){
  //count down running
}
public void onFinish (){
  //what to do after countdown finishes
}
}.start();

/* The countdown method is preferable cause it's being deconstructed immediately from memory right after its
job is done unlike the handlers which are stuck in the memory. it makes the App more slow*/