Constructors in Java are special methods that are used to initialize objects. They are invoked when an object is created and have the same name as the class. Constructors can be overloaded and can take parameters to initialize object state. They ensure objects are ready for use by setting initial values and supporting inheritance. Constructors have no return type and implicitly return an instance of the class. If no constructors are defined, a default no-arg constructor is provided.

1. UNDERSTANDING JAVA
CONSTRUCTORS
BY: ZANDRO APOSTOL

2. WHAT IS A CONSTRUCTOR?
• A constructor in Java is similar to a method that is invoked when an
object of the class is created.
• In Java, a constructor is a special kind of method. It is a member
function of a class with the same name as the class, and it is
responsible for initializing the object of the class.
• They set initial values, support inheritance, and ensure objects are
ready for use.

3. HERE ARE SOME KEY CHARACTERISTICS
OF CONSTRUCTORS:
1. Class Name: A constructor has the same name as the class it belongs to.
2. No Return Type: Unlike regular methods, constructors don't have a return
type, not even ‘void’. They implicity return an instance of the class.
3. Initialization: The primary purpose of a constructor is to initialize the state
of an object. It is automatically called when an object is created using the ‘new’
keyword.
4. Default Constructor: If a class doesn't explicitly define any constructors,
Java provides a default constructor with no parameters.
5. Overloading: Constructors, like regular methods, can be overloaded by
defining multiple constructors with different parameter lists.

4. SYNTAX
public – This can be access modifier, which
determines the visibility of the constructor. It can be
‘public’, ‘private’,’protected’.

5. • Example:
Class with constructor

6. USING THE CONSTRUCTOR:
You can create an instance of the class and invoke the constructor like this:

7. PARAMETERIZED CONSTRUCTOR:
You can also create
constructors that accept
parameters. This allows
you to initialize the object
with specific values at the
time of creation. Here's
an example:

8. Now, when you create a car object, you can pass values to initialize it:

9. EXAMPLE 1: JAVA CONSTRUCTOR
Name of the
class to be
construct
The
constructor
name, must
same to the
class name
Creating a
new object

11. TYPES OF CONSTRUCTOR
In Java, constructors can be divided into 3 types:
1. No-Arg Constructor
2. Parameterized Constructor
3. Default Constructor

12. •1. Java No-Arg Constructors
• Similar to methods, a Java constructor may or may not have any
parameters (arguments).
• If a constructor does not accept any parameters, it is known as a no-
argument constructor. For example,

13. •Example 2: Java private no-arg constructor
-Example of private no-arg
Constructor

14. 2. JAVA PARAMETERIZED
CONSTRUCTOR
• A Java constructor can also accept one or more parameters. Such
constructors are known as parameterized constructors (constructor
with parameters).
-Example of parameterized
Constructor

15. 3. JAVA DEFAULT CONSTRUCTOR
• If we do not create any constructor, the Java compiler automatically
create a no-arg constructor during the execution of the program. This
constructor is called default constructor.
-Example of default
Constructor

16. CONSTRUCTORS OVERLOADING IN
JAVA
• Similar to Java method overloading, we can also create two or more
constructors with different parameters. This is called constructors
overloading.

17. -Example of overloading
Constructor

18. THANK YOU!