object-reference

I would like to understand how primitive and object reference variable behaves differently. I have used the below code from OCA/OCP Java SE7 by Kathy Sierra as an example: public class VariableTesting { public static void main(String[] args) { int a = 10; System.out.println("a= " + a); int b = a; b = 30; System.out.println("a= " + a + " after change it to b and b is " + b); Dimension a1 = new Dimension(5, 10); System.out.println("a1.height = " + a1.height); Dimension b1 = a1; b1.height = 30; System.out.println("a1.height= " + a1.height + " after change to b1"); } } In the above piece of code,

I have a Public Class "General" in which is a Public Sub "updateDynamics". When I attempt to reference it in the code-behind for a page like so: updateDynamics(get_prospect.dynamicsID) I get the following error: reference to a non-shared member requires an object reference You either have to make the method Shared or use an instance of the class General : Dim gen = New General() gen.updateDynamics(get_prospect.dynamicsID) or General.updateDynamics(get_prospect.dynamicsID) Public Shared Sub updateDynamics(dynID As Int32) ' ... ' End Sub Shared(VB.NET) Go to the Declaration of the desired object

When I try to build my VB.NET solution, I get the error, "Object reference not set to an instance of an object." but in the Error List pane, the File, Line, Column, and Project columns are blank: How can I solve the problem if it won't tell me where it is? UPDATE I selected the Project, then "Show Project Dependency Diagram" and got this: I don't know what I'm looking at. UPDATE 2 I don't know if this is unusual or to be expected, but if I mash F5, I do get a page in a browser ( http://localhost:2030/ ) without any err msg; granted, the page looks like North Dakota from an airplane in winter.