Pergunta de entrevista da empresa Quantum Machines

//What will be minimum and maximum number //that will be printed? class AbcThread extends Thread{ private int[] _arr; public MyThread(int[] arr){ this._arr = arr; } public void run(){ for (int i=0;i<20 ; i++) { this._arr[0]++; } } public static void main(String[] args) { int[] arr ={0}; try { MyThread t1 = new MyThread(arr); MyThread t2 = new MyThread(arr); t1.start(); t2.start(); t1.join(); t2.join(); }catch(Exception ex){ System.out.println("Exception "+ex); } System.out.println(arr[0]); } }