java 小问题

Question

public class ArrayParser{
    public static void main(String args[]){
        double[][] d;
        
        String s = "1,2;3,4,5;6,7,8";
        String[] sFirst = s.split(";");
        d = new double[sFirst.length][];
        for(int i = 0; i<sFirst.length ; i++){
                String[] sSecond = sFirst[i].split(",");
                    d[i] = new double [sSecond.length];
                for(int j =0; j<sSecond.length; j++){
                    d[i][j] =Double.parseDouble(sSecond[j]);
            
            }
            }
        for( int i =0 ;i<d.length; i ++){
            for(int j=0 ;i<d[i].length; j++){
            System.out.print(d[i][j] +"");
                }
                System.out.println();
                        }
    }
}

Answer 1

for(   j.length)

Answer 2

for( int i =0 ;i<d.length; i ++){            for(int j=0 ;j<d[i].length; j++){            System.out.print(d[i][j] +"");                }                System.out.println();                        }