Figura de Asteriscos en Java

package figuradeasteriscos;

import javax.swing.JOptionPane;

public class Main {
    public static void main(String[] args) {
        String sal = "", ast = "*";
        int n = Integer.parseInt(JOptionPane.showInputDialog("Ingrese un valor"));
        for (int i = 1; i <= n; i++) {
            sal = sal + ast + "\n";
            ast = ast + "*";
        }
        System.out.println("\n" + sal);
    }
}