Something

public class test
{
	public static void main(String[] args)
	{
		for (int i = 0; i < 50; i++) {
			String s = "\r";
			int j;
			for (j = 0; j < i; j++)
				s += "#";
			for (int k = 0; k < 50-j; k++)
				s += ' ';
			System.out.print(s);
			System.out.flush();
			long curr = System.currentTimeMillis();
			while (System.currentTimeMillis() < curr+500)
				;
		}
		System.out.println("");
	}
}