Appfreez by Enter other Thread

Question

When the Compiler enter doInBackground the App freez

Main Class (ParkTicketAlarm):

Timer timer = new Timer();
  timer.doInBackground(ParkTicketAlarm.this);

AsyncClass (Timer)

protected String doInBackground(ParkTicketAlarm... params) {
    java.sql.Time   time = new java.sql.Time(System.currentTimeMillis());
    while(time.getMinutes()!=28){

        try {
                wait(2000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            time = new java.sql.Time(System.currentTimeMillis());
        }
    params[0].expired();

    return null;    
    }

}