Algorithm: Triangle in Java

Problem: Create a triangle like below in Java:
   *
 ***
*****

Solution: Java Program:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;


public class triangle {


    public static void main(String[] args) {
        try {
            BufferedReader object = new BufferedReader
                    (new InputStreamReader(System.in));
            System.out.println("enter the number");
            int a= Integer.parseInt(object.readLine());
            for (int i = 1; i <= a; i++) {
                for (int j = i; j < a; j++) {
                    System.out.print(" ");               
                }
                for (int k = ((i*2)-1); k > 0 ; k--) {
                    System.out.print("*");                       
                }
                System.out.println("");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}


The run-time execution on my Linux machine (core2duo 1.6GHz, 3GB ram) is around 0.60 secs for a triangle of length 100. Can you improvise this algo further?