非法字符错误：“\u200b”

我正在面向对象编程类中为小行星游戏制作小行星场，但我收到一个非法字符错误：“\u200b”。这个问题似乎发生在第12行。（import java.awt.Point; 和公共类 Asteroid 之间的线扩展了 PolyBlob）

/*
 * University of Central Florida
 * COP3330 - Spring 2016
 * Author: Aundray Ortiz
 */
package asteroidfield;

import java.util.Random;
import blobzx.PolyBlob;
import blobzx.BlobUtils;
import java.awt.Point;
​
public class Asteroid extends PolyBlob
{
    private static final Random random = new Random();

    public Asteroid(int a, int b, double c)
    {
        super(-100,-100,c);
        int sides = 5 + random.nextInt(5);
        int[] x = new int[sides];
        int[] y = new int[sides];
        int going = 0;
        double direct = 0;
        double region = (Math.PI * 2)/sides;
        for(int num = 0; num<sides;num++)
        {
            going = 5 + random.nextInt(16);
            direct = (num * region) + (Math.random() * region);
            Point p = BlobUtils.rotatePoint(going, direct);
            x[num] = p.x;
            y[num] = p.y;
        }

        setPolygon(x, y);
        setRate(c);
        setDelta(a,b);
    }
}