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The copy constructor copies every value from one object to another.

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In the previous lesson, you decided to sell a second Nissan, so you made a new object and passed in

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the same values.

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Now, I have to admit, passing every valley twice is a bit annoying.

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In this lesson, you're going to get a copy constructor and call it.

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Constructor overload means having more than one constructor.

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So far, you created one constructor when you pass in for argument's, Java knows to call the constructor

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with four parameters.

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Now, a class can have many constructors, as many as you want, each constructor shares the same name

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as the class that it's in, but it takes different parameters.

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You can have a constructor with four parameters, three parameters, two parameters, one parameter

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or even zero.

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And the fact that each instructor has the same name, how does Javin know which one I intend to call?

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Java looks at the arguments you pass, then it's going to know which constructor you want it to call.

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For example, you can create a car object and pass in two arguments to the constructor.

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Java's going to know to run the constructor with two parameters.

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Why does this matter?

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Well, we're about to add a new constructor.

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And that constructor is the copy constructor, the copy constructor copies every value from one object

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to another.

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The copy constructor takes one parameter, the object you want to copy values from the source.

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As you're creating a new car object, passing the object, you want to copy values from Jarvis's the

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argument and it knows to run the copy constructor, the parameter source stores, a reference that points

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to the Nissan object.

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Then it copies every value from the source object into the current object.

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So inside the car class, I'm going out of constructor.

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Public car.

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And this constructor, for it to run, it expects to receive another car object, car source.

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Because of this object is going to be the source from which we update the fields of our new object.

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All right, so we're going to set every field in the current object equal to a value from the source

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object.

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We're going to set the make of the object we just created equal to the make from the source object that

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gets passed in.

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We'll do the same thing for price.

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Year and color.

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And now we can call the copy constructor, certainly Nissan, to equal to a new object in UKAR.

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And passing the original Nissan is the source object that we want to copy values from.

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Reinier code.

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And it works every value from the source object gets copied over into the new object.

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You set Nisan to equal to a new object and passed the Nissan as an argument, Javert sees the argument

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and knows to run the copy constructor.

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The parameters source stores a reference that points to the Nissan object, this refers to the new object

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we just created, the current object, the one that's calling the constructor and the copy constructor,

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copies every field from the source object into the current object.

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And in the end, Nissan, too, is equal to a copy of the Nissan object.

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This is a way better solution to the reference trap in the old solution, we were using the first constructor

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to create copies.

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We were passing in four identical arguments.

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So Jabarin in the constructor with four parameters.

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This method is a bit annoying, in my opinion.

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I like the copy constructor because it copies every value from a source.

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This is actually the accepted way of copying objects, so we're going to update our table.

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And this lesson, you added a copy constructor and used it, the copy constructor takes one parameter,

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the object that you want to copy.

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As you're creating a new car object, passing the object that you want to copy values from Java, the

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argument, and it knows to run the copy constructor.

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The parameter source is a reference that points to the Nissan object, and this refers to the new object

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you just created, the current object, the one that's calling the constructor and the copy constructor,

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copies every field value from the source object into the current object.

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This is the best way and the accepted way to copy objects.