NullPointerExeption on initialization?

Question

Java

I'm new to programming (I'm learning about the possibilities of OOP), please explain what is the cause of this error. Since when designing, the IDE does not produce any syntax errors. The code is the following:

public static Male[] m;
public static Female[] f;

public static void main(String[] args) {

for(int i = 0; i<10; i++)
     m[i] = new Male("Adam",1333,23.00f);
        
for(int i = 0; i < m.length; i++)
     System.out.println(m[i].WhoAreYou());

What is the reason for such an error?

Answer 1

The size of an array must be specified before it is used.