 So let's say for a second that I want to take this credit card and you know credit card you might change them You know they expire so I want to create something called a setter. I want to make a setter for my credit card Public void because I don't expect anything to change. I just want to change it set Credit card so one of the things I'm going to need to do is I'm going to need to pass it a Parameter and what I'm going to call this is actually credit card now here in lies a problem. So if I credit card equal Credit card seems okay. That's what we're calling it up here and here I just want to go ahead and also make myself a little getter So we can see this in action for just a second get credit card. I know in my last video I talked about how we don't always want to do that Something a little personal, but okay. We've got this get credit card. We've got this set credit card Now inside of my test student. I'm going to Get the cc, but right above it. I'm also going to do set credit card equal to One at one two three four five six seven eight nine zero one two three four Five six five five So I've just changed the credit card is what I'm saying I've changed the credit card and then I want you to then display that back to me. So if I compile test student up Everything's honky-dory just a double check. I always like to run through it a little twice When I run test student, I should see one two three four five six seven eight nine zero one two three four five And I don't I see Randy Savage because that's Randy Savage But my credit card didn't change and the issue is we're now dealing with scope this credit card Overrides our class variable and that's where that idea of data encapsulation comes into play So how do we how do we resolve this what we do this by utilizing something called This this keyword this dot Credit card that's actually referring to this version of credit card versus this version of credit card And so one of the things you can do with this is this is actually a good tool to put this inside of say your Constructor because what happens if instead of F name I? Want to do Something like this So all of a sudden now and just to kind of keep with that trick that that Trying to thought now what happens is when I pass a parameter instead of calling it F name I've named it first name, but how does that differ from the actual class variable first name? Well, this one is the local version This one refers to the class version and so the same thing is going to happen now now that I've changed my set credit card This one is sort of the local variable and this is the class variable the instance variable and it changes versus This just only existing for this one method So now when we compile this up and now when we run it notice how Randy Savage has now be gotten his credit card changed and all is right in the world