import java.util.Arrays;

class Ideone {
	public static void main (String[] args) {
		System.out.println(padLeft("This", 10, '0'));
		System.out.println(padLeft("This is", 10, '0'));
		System.out.println(padLeft("This is a", 10, '0'));
		System.out.println(padLeft("This is a test", 10, '0'));
	}
	public static String padLeft(String value, int width, char pad) {
		if (value.length() >= width)
			return value;
		char[] buf = new char[width];
		int padLen = width - value.length();
		Arrays.fill(buf, 0, padLen, pad);
		value.getChars(0, value.length(), buf, padLen);
		return new String(buf);
	}
}