Write Point Array - arrays

Question

I work on a trainigs code to compare the distance of an unspecific number of points from the zero point.
The error appears when i want to write the input point values into the Point array and i don't know how to handle it:
points[i].setLocation(x,y);
Error says: Exception in thread "main" java.lang.NullPointerException
at minDis.minDis.main(minDis.java:59)
I would be thankful for any advices.
import java.awt.Point;
import java.util.Scanner;
public class minDis {
private static final Point Point = null;
static double dis(Point p){
double dis= Math.sqrt(p.x*p.x+p.y*p.y);
return dis;
}
static double minDist(Point[] points, int anz){
double minimum= dis(points[0]);
for(int z=0; z<anz; z++){
if (dis(points[z]) < minimum)
minimum=dis(points[z]);
}
return minimum;
}
static double minDistPoint(Point[] points, int anz){
double minimum= dis(points[0]);
int DistPoint = 0;
for(int z=0; z<anz; z++){
if (dis(points[z]) < minimum)
minimum=dis(points[z]);
DistPoint=z;
}
return DistPoint;
}
public static void main(String[] args) {
Point points[]=null;
Scanner scan= new Scanner(System.in);
System.out.println("How many Points do you want to compare?");
int anz= scan.nextInt();
for(int i=0; i<anz; i++){
System.out.println("Type in Point "+anz);
System.out.println("X: ");
int x= scan.nextInt();
System.out.println("Y: ");
int y= scan.nextInt();
**points[i].setLocation(x,y);**
}
scan.close();
System.out.println("It is Point "+minDistPoint(points, anz)+" with a distance of "+ minDist(points, anz));
}
}

Answer 1

In your code snippet, you are not allocating memory for the Pointer Object array. That's why you are getting NullPointerException. Therefore, you need to allocate memory to the array of Point objects in your code.
But, remember when you create a array of objects like this,
Object[] arr = new Object[10];
Here you are just creating 10 Object References. Now, to do any operations with individual array elements, you need to allocate memory to each object also, For Example,
arr[i] = new Object();
So, use the following snippet as the corrected version for your code.
public static void main(String[] args) {
Point[] points;
Scanner scan= new Scanner(System.in);
System.out.println("How many Points do you want to compare?");
int anz= scan.nextInt();
points = new Point[anz];
for(int i=0; i<anz; i++) {
points[i] = new Point();
System.out.println("Type in Point "+anz);
System.out.println("X: ");
int x= scan.nextInt();
System.out.println("Y: ");
int y= scan.nextInt();
points[i].setLocation(x,y);
}
scan.close();
System.out.println("It is Point "+ minDistPoint(points, anz)+" with a distance of "+ minDist(points, anz));
}