Constructors - JAVA: Easy Java Programming for Beginners, Your Step-By-Step Guide to Learning Java Programming (2015)

JAVA: Easy Java Programming for Beginners, Your Step-By-Step Guide to Learning Java Programming (2015)

Chapter 10. Constructors

One of the many Java concepts that this chapter introduces is the importance of constructors. Constructors are one of the many method-like things that allow the declaration of elements or the creation of new objects.

Constructors work as commands that need to match the other elements in a predefined function whenever they are invoked. They are also either defined or provided by default in Java programming language. Default constructors can set parameters but are not designed to carry out specific tasks nor perform unique actions. They cannot even take any argument. An explicit version of a constructor is required to allow the execution of particular commands and functions.

The main goal of constructors is to initialize the call to a fellow constructor by declaring special (). Upon the acknowledgement of a new constructor, a programmer is encouraged to create and set a parameter for the introduction of an object.


This constructor is used to pertain to a particular program component and most of the time it is used as reference to other constructors in a similar class, but in different parameter list.


public class dolphin {

string name;

dolphin (string input) {

dolphin () {

this (“kevin / kim”);


public static void int main (string arguments []) {

dolphin p1 = new dolphin (“abigail”)

dolphin p2 = new dolphin ();



In the example above, the constructor use of this refers to other constructors named kevin and kim under the public class dolphin. The strings have declared arguments and two batches of parameters are set – abigail for p1 and default constructor for p2.


This constructor is usually identified in the first line of the programming code since Java compilers do not return a value if super is not declared initially. This keyword invokes a superclass constructor.


public class super superclass_penta {

super superclass_penta [] {}


class tonics extends superclass_penta

tonics () {

super [];


In this example, super was used as a constructor that defines superclass_penta. It is categorized under the class tonics. Although a class is already known to be previously defined, the capability of a special constructor performance is possible.

This chapter has explained to you two constructors that you can use in Java programming – this and super. It is imperative that you know when to use these constructors for your program to run properly.

Here is a quick recap of what we covered in case you need a refresher on a certain step:

1. You now have an understanding of how Java technology was developed

2. You learnt how to install and setup Java software and other required program tools

3. You learnt how to create a simple Java program

4. You learnt how to include a user input feature in your Java program

5. You learnt how to properly declare and manipulate variables

6. You learnt how to modify the complexity of your Java program through operators

7. You learnt how to perform non-sequential programming using flow control statements

8. You learnt how to differentiate and use appropriately Java access modifiers

9. You learnt how to work around with classes and objects

10. You also learnt how to correctly employ constructors in your Java program