for语句和if语句画正方形菱形

public static void main(String[] args) {
    int n =8;
//    空心正方形
    for(int i=0;i<=n;i++){
        if(i==0||i==n){
            for(int j=0;j<=n;j++){    
                System.out.print("* ");
            }
        }
        else{
            for(int j=0;j<=n;j++){    
                if(j==0){
                    System.out.print("*");
                }
                else if(j==n){
                    System.out.print(" *");
                }
                else{
                    System.out.print("  ");
                }
            }
        }
        System.out.println("");    
    }
//    菱形
for(int i=1;i<=n;i++){
    for(int j=1;j<=n-i;j++){
        System.out.print(" ");
    }
    for(int j=n-i+1;j<=n+i-1;j++){
        System.out.print("*");
    }
    System.out.println("");
}
for(int i=1;i<n;i++){
    for(int j=1;j<=i;j++){
        System.out.print(" ");
    }
    for(int j=i+1;j<=2*n-i-1;j++){
        System.out.print("*");
    }
    System.out.println("");
}
//空心菱形
for(int i=1;i<=n;i++){
for(int j=1;j<=n-i;j++){
    System.out.print(" ");
}
for(int j=n-i+1;j<=n+i-1;j++){
    if(j==n-i+1||j==n+i-1){
        System.out.print("*");
        }
    else{
        System.out.print(" ");
    }
}
System.out.println("");
}
for(int i=1;i<n;i++){
for(int j=1;j<=i;j++){
    System.out.print(" ");
}
for(int j=i+1;j<=2*n-i-1;j++){
    if(j==i+1||j==2*n-i-1){
        System.out.print("*");
        }
    else{
        System.out.print(" ");
    }
}
System.out.println("");
}