Java对象数组java.lang.NullPointerException

这样做

public class Blocks {public static Block[] b = new Block[8];static {   // Instantiating the objects present in the array   for(int i=0; i<b.length; i++)       b[i] = new Block();}public Blocks() throws IOException {   // Now you can access them    new Air  (b[0]);    new Stone(b[1]);    new Grass(b[2]);    new Dirt (b[3]);}

您忘记实例化数组中存在的对象。所以它提示空指针异常