Recursive Constructor Invocation in Java

In Java, constructors are special methods that are called when an object is created. They are used to initialize the object state and carry out any important setup. One interesting feature of constructors in Java is the ability to name some other constructor inside the same class, that is called recursive constructor invocation.

Recursive constructor invocation is a useful function of Java and different object-orientated programming languages, however it needs to be used cautiously to keep away from errors and infinite loops. It may be especially beneficial for simplifying the creation of objects with a subset of parameters, however it is far essential to continually make sure that the recursion subsequently reaches a base case and does now not retain indefinitely.

Approach:

ALGORITHM:

Step 1: Start the program.

Step 2: Define a class named Product.

Step 3: Inside the Product class we have to declare the two instance variables name to store the name of the product and price to store the price of the product.

Step 4: now create the constructor with two parameters name and price.

Step 5: Inside the constructor, perform recursive constructor invocation by calling this(name, price).

Step 6: Assign the name parameter to the call instance variable and the price parameter to the charge example variable.

Step 7: Define a main method to test the Product class.

Step 8: Inside the main method, create a Product object named product with the name "Phone" and price 999.99.

Step 9: Print the product name and price using the System.out.println statement.

Step 10: End the program.

Implementation:

The implementation of the above steps are given below

FileName: Product.java

import java.util.*;

public class Product 
{
    String name;
    double price;

    // Constructor with name and price parameters
    public Product(String name,double price) 
    {
        this(name,price); // Recursive constructor invocation
        this.name=name; // Assign name parameter to instance variable
        this.price=price; // Assign price parameter to instance variable
    }

    public static void main(String[] args) 
    {
        // Create a Product object with name "Phone" and price 999.99
        Product product=new Product("Phone", 999.99);

        // Print the product name and price
        System.out.println("Product:"+product.name);
        System.out.println("Price:$"+product.price);
    }
}

Output:

ERROR!
javac /tmp/0qLw40OAxb/Product.java
/tmp/0qLw40OAxb/Product.java:7: error: recursive constructor invocation
public Product(String name,double price) 
           ^
1 error

Explanation:

The above code gives the recursive constructor invocation error now we are going to modify the code and given below

ALGORITHM:

Step 1: Start the program.

Step 2: Define a class named Product.

Step 3: Inside the Product class we have to declare the two instance variables name to store the name of the product and price to store the price of the product.

Step 4: now create the constructor with two parameters name and price.

Step 5: Inside the constructor, perform recursive constructor invocation by calling this(name, price).

Step 6: Assign the name parameter to the call instance variable and the price parameter to the charge example variable.

Step 7: Within the same constructor now create a new Product object named product1 with the name "Laptop" and price 2016.54.

Step 8: Define a main method to test the Product class.

Step 9: Inside the main method, create a Product object named product with the name "Phone" and price 999.99.

Step 10: Print the product name and price using the System.out.println statement.

Step 11: End the program.

Implementation:

The implementation of the above steps given below

FileName: Product.java

import java.util.*;

public class Product 
{
    String name;
    double price;

    // Constructor with name and price parameters
    public Product(String name,double price) 
    {
        this.name=name; // Assign name parameter to instance variable
        this.price=price; // Assign price parameter to instance variable
        Product product1=new Product("Laptop",2016.54);
    }

    public static void main(String[] args) 
    {
        // Create a Product object with name "Phone" and price 999.99
        Product product=new Product("Phone", 999.99);

        // Print the product name and price
        System.out.println("Product:"+product.name);
        System.out.println("Price:$"+product.price);
    }
}

Output:

Exception in thread "main" java.lang.StackOverflowErrorat Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)
	at Product.(Product.java:13)

Basically, Stack overflow error occurs when we are not able to terminate all the conditions to the recursive function or the template, It will leads to the infinite loop and responsible for causing error.

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