Inheritance and ConstructorsΒΆ

How do you initialize inherited private fields if you don’t have direct access to them in the subclass? In Java you can put a call to the parent constructor using the keyword super as the first line in a subclass constructor to initialize inherited fields. See the constructor in Employee below for an example.

The super(theName) in the Employee constructor will call the constructor that takes a String object in the Person class to set the name.

If a class has no constructor in Java, the compiler will add a no-argument constructor. A no-argument constructor is one that doesn’t have any parameters.

public Person()

The code above is a no-argument constructor for the Person class. Remember that constructors don’t have a return type and the constructor name must match the class name.

If a subclass has no call to a superclass constructor using super as the first line in a subclass constructor then the compiler will automatically add a super() call as the first line in a constructor. So, be sure to provide no-argument constructors in parent classes or be sure to use an explicit call to super as the first line in the constructors of subclasses.

You can step through this code in the Java Visualizer by clicking on the following link Constructor Test1.

You can step through this code using the Java Visualizer by clicking the following link Named Point.

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