Google Polyline encoder written in Java

Utils.java

public class Utils {
  
	private static final double DEFAULT_PRECISION = 1E5;
  
  private static String encodeDiff(int diff) {
		StringBuilder str = new StringBuilder();
		int shifted = diff << 1;
		if (diff < 0) {
			shifted = ~shifted;
		}

		int rem = shifted;

		while (rem >= 0x20) {
			str.append((char) ((0x20 | (rem & 0x1f)) + 63));
			rem >>= 5;
		}

		str.append((char) (rem + 63));
		return str.toString();
	}

	public static String encodePolyline(LineString encoded) {
		StringBuilder str = new StringBuilder();

		int lastLat = 0;
		int lastLng = 0;

		for (Coordinate coor : encoded.getCoordinates()) {
			int lat = (int) Math.round(coor.getY() * 1E5);
			int lng = (int) Math.round(coor.getX() * 1E5);

			str.append(encodeDiff(lat - lastLat));
			str.append(encodeDiff(lng - lastLng));

			lastLat = lat;
			lastLng = lng;
		}

		return str.toString();
	}
}