why not using new when creating an instance ?

Question

Dear experts,

 

I have this question which is probably very easy for most of you but it beats me cos I am used to Java way of creating a new instance by doing like this :

 

Category c = new Category();

 

However, I come across the below code where I am not sure why it is written this way :

 

public class PurchaseOrderBL

{

 

UniEntities db = new UniEntities();

 

int purchaseOrderId;

 

Category category;

 

My question is why not Category category = new Category(); ?

 

Here's the Category class:

 

public class Category

{

private int categoryId{

get { return categoryId; }

set { categoryId = value; }

}