سؤال .. ارجو المساعدة

مرحبا يا شباب .. انا عندي اكمن سؤال JAVA يا ريت اتجاوبوني عليها ضروري :)

import javax.swing.JOptionPane;

public class Palindrome
{
	public static void main(String args[])
	{
		String number = JOptionPane.showInputDialog("Enter a five digits integer:");
		int n1 = Integer.parseInt(number);
		int mul = 10000;
		int a,b,c,d,e;
		while ( log(n1) / log(10) + 1 != 5)
		{
			number = JOptionPane.showInputDialog("Enter a five digits integer:");
			n1 = Integer.parseInt(number);
		}
		a = n1 / mul; // FIRST DIGIT
		n1 = n1 % mul;
		mul = mul / 10;
		b = n1 / mul; // SECOND DIGIT
		n1 = n1 % mul;
		mul = mul / 10;
		c = n1 / mul; // THIRD DIGIT
		n1 = n1 % mul;
		mul = mul / 10;
		d = n1 / mul;
		n1 = n1 % mul; // FORTH DIGIT
		mul = mul / 10;
		e = n1 / mul; // FIFTH DIGIT
		if (a == e && b == d)
		JOptionPane.showMessageDialog(null,number + " Is a palindrome number");
		else
		JOptionPane.showMessageDialog(null,number + " Is not a plindrome number");

	}
}

Question2:

How to I make a program that prints the factorials for the numbers from 1 to 5

1 = 1 = 1

2 = 2 * 1 =2

3 = 3 * 2 * 1 = 6

And like this....

Here where I'am:

public class Factorials
{
	public static void main(String args[])
	{
		for (int counter = 1; counter <= 5; counter++)
		{

		}
	}
}