Usage of Java this keyword

Question

In a class constructor, I am trying to use:

if(theObject != null)
    this = theObject; 

I search the database and if the record exists, I use theObject generated by Hibernate Query.

Why can't I use this?

Answer 1

It's because 'this' is not a variable. It refers to the current reference. If you were allowed to reassign 'this', it would no longer remain 'this', it would become 'that'. You cannot do this.

Answer 2

this is not a variable, but a value. You cannot have this as the lvalue in an expression.