Java: Calling super()

super() calls the constructor of the base class.

Another Example

Here's an expanded version with printouts and constructor arguments.

class Animal {
    public Animal(String arg) {
        System.out.println("Constructing an animal: " + arg);
    }
}

class Dog extends Animal {
    public Dog() {
        super("From Dog constructor");
        System.out.println("Constructing a dog.");
    }
}

public class Test {
    public static void main(String[] a) {
        new Dog();
    }
}

Prints the following:

Constructing an animal: From Dog constructor
Constructing a dog.

The Fine Print

• The call to super() must be the first statement in the constructor.
• If you give arguments to super("hello", 5), it will invoke the base constructor that accepts a String and an int.
• super() without arguments calls the base class' no-arg constructor. Such constructor only exists if A) you have not defined any constructor, or B) you have explicitly defined a no-arg constructor. If neither of these are true, then super() will fail with a compile error.