Different ways to create an object in Java

Ways to create an object: Here, we are going to learn what are the different ways to create an object of a class in Java? By Preeti Jain Last updated : January 14, 2024

Objects creation of a class in Java

There are five different ways to create an object and we will see the ways to create an object given below:

Using new keyword
Using newInstance() method of Class
Using clone() method
Using newInstance() method of Constructor class
Using deserialization

1) Using new keyword

new is a keyword which is introduced in Java.
We mostly use new keyword to create an object.
By using new keyword we can call any constructor we want to call.

Java program to create an object using new keyword

class CreateObjectByNew {
    // Default Constructor
    CreateObjectByNew() {
        System.out.println("We are creating an object by using new keyword");
    }
}

class Main {
    public static void main(String[] args) {
        // Creating an object of CreateObjectByNew class
        CreateObjectByNew cobn = new CreateObjectByNew();
    }
}

Output

E:\Programs>javac Main.java

E:\Programs>java Main
We are creating an object by using new keyword

2) Using newInstance() method of Class

This newInstance() method is available in Class.
By using newInstance() method of Class it can call the no-argument constructor or default constructor.
It creates a new instance of the class.

Java program to create an object using newInstance() method of Class

class NewInstanceMethodOfClass {
    // Default constructor
    NewInstanceMethodOfClass() {
        System.out.println("Object by using newInstance() method of Class");
    }
}

class Main {
    public static void main(String[] args) throws Exception {
        // Creating an object of Class class and 
        // we are passing our class as an argument 
        // in forName() method of Class
        Class cl = Class.forName("NewInstanceMethodOfClass");

        // Now we are calling newInstance() method of Class 
        // and returns a reference of our created class
        NewInstanceMethodOfClass nimoc = (NewInstanceMethodOfClass) cl.newInstance();
    }
}

Output

E:\Programs>javac Main.java

E:\Programs>java Main
Object by using newInstance() method of Class

3) Using clone() method

This method is available in java.lang.Cloneable interface.
We have override clone() method of Cloneable interface in our class.
It is the easiest way of copying an object.

Java program to create an object using clone() method

class CreateObjectByClone implements Cloneable {
    String name;
    CreateObjectByClone(String name) {
        this.name = name;
    }

    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

    public static void main(String[] args) throws Exception {
        CreateObjectByClone cobc1 = new CreateObjectByClone("Preeti");
        CreateObjectByClone cobc2 = (CreateObjectByClone) cobc1.clone();
        System.out.println("The values before clone() in cobc1" + " " + cobc1.name);
        System.out.println("The values after clone() in cobc2" + " " + cobc2.name);
    }
}

Output

E:\Programs>javac CreateObjectByClone.java

E:\Programs>java CreateObjectByClone
The values before clone() in cobc1 Preeti
The values after clone() in cobc2 Preeti

4) Using newInstance() method of Constructor class

It also creates a new instance of a class similar to the newInstance() method of the Class class.
By using newInstance() method of Constructor class it can call any number of argument constructor.

Java program to create an object using newInstance() method of Constructor class

import java.lang.reflect.Constructor;

class NewInstanceMethodOfConstructor {
    String fname, lname;
    // passName() method with two argument
    public void passName(String fname, String lname) {
        this.fname = fname;
        this.lname = lname;
    }
}

class Main {
    public static void main(String[] args) {
        try {
            // calling constructor and returns a reference of Constructor class
            Constructor cons = NewInstanceMethodOfConstructor.class.getDeclaredConstructor();

            // Now we are calling newInstance() method of Class 
            // and returns a reference of our created class
            NewInstanceMethodOfConstructor nimoc = (NewInstanceMethodOfConstructor) cons.newInstance();

            nimoc.passName("Preeti", "Jain");

            System.out.println("My full name is :" + nimoc.fname + " " + nimoc.lname);
        } catch (NoSuchMethodException ex) {

            System.out.println(ex.getMessage());
        } catch (SecurityException ex) {

            System.out.println(ex.getMessage());
        } catch (InstantiationException ex) {

            System.out.println(ex.getMessage());
        } catch (IllegalAccessException ex) {

            System.out.println(ex.getMessage());
        } catch (IllegalArgumentException ex) {

            System.out.println(ex.getMessage());
        } catch (Exception ex) {

            System.out.println(ex.getMessage());
        }

    }

}

Output

E:\Programs>javac Main.java

E:\Programs>java Main
My full name is :Preeti Jain

5) Using deserialization

When we serialize an object then after we deserialize it so the run time environment JVM create a separate object for that.
In the case of deserialization, it does not call any constructor to create an object.
Our class must implements Serializable interface.
We will use two classes named ObjectOutputStream and ObjectInputStream and their two methods writeObject() of ObjectOutputStream and readObject() of ObjectInputStream.
writeObject(): This method serialize an object and transfer it to the output stream.
readObject(): This method references an object out of the stream and then deserialize it.

Java program to create an object using deserialization

// Java program to demonstrating serialize and deserializing an object
import java.io.*;

class Serialize implements Serializable {
    public String fname, lname;

    public Serialize(String fname, String lname) {
        this.fname = fname;
        this.lname = lname;
    }
}

public class Deserialization {
    public static void main(String[] args) {
        Serialize serialize = new Serialize("Ronit", "Jain");

        try {
            FileOutputStream fos = new FileOutputStream("E:\\Programs\\myjava.txt");
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(serialize);
            oos.close();
            fos.close();
        } catch (IOException ex) {

            System.out.println(ex.getMessage());
        }

        serialize = null;

        try {
            FileInputStream fis = new FileInputStream("E:\\Programs\\myjava.txt");
            ObjectInputStream ois = new ObjectInputStream(fis);
            serialize = (Serialize) ois.readObject();
            ois.close();
            fis.close();
            System.out.println("His full name is :" + serialize.fname + " " + serialize.lname);
        } catch (IOException ex) {

            System.out.println(ex.getMessage());
        } catch (ClassNotFoundException ex) {

            System.out.println(ex.getMessage());
        }
    }
}

Output

E:\Programs>javac Deserialization.java

E:\Programs>java Deserialization
His full name is :Ronit Jain

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