Null Reference Exception-S1 P2

When you are in the middle of coding a .aspx page or a code-behind page, either vb, c# or j#. A regular and of-course irritating error will appear and tries to drink your time. It is nothing but the Null Reference Exception. A lot of issues can be the root for this issue but concerned to my case, mostly I forgot to instantiate the dataset or table adapter by using the "new" operator.
Ex:
example.aspx.vb

dim teacher as new dataset1.teacherdatatable

If you miss new here it shows the above error. The basic reason that i noticed was that some of the objects should be constructed by using the new operator during each declaration.