JavaBeat

  • Home
  • Java
    • Java 7
    • Java 8
    • Java EE
    • Servlets
  • Spring Framework
    • Spring Tutorials
    • Spring 4 Tutorials
    • Spring Boot
  • JSF Tutorials
  • Most Popular
    • Binary Search Tree Traversal
    • Spring Batch Tutorial
    • AngularJS + Spring MVC
    • Spring Data JPA Tutorial
    • Packaging and Deploying Node.js
  • About Us
    • Join Us (JBC)
  • Privacy
  • Contact Us

Get Constructors using Reflection

March 16, 2014 by Krishna Srinivasan Leave a Comment

This example shows how to get the constructors in a class and invoke it. Note that java.lang.reflect.Constructor defines a method newInstance() which is used for creating instance for an object. Before that you have to get the list of constructors in a class. We have two methods defined in the Class class. If we use getConstructors() method, it returns only the public constructors in that class. If we use getDeclaredConstructor() method, it returns all the constructors in that class.

Lets look at the example code.

[code lang=”java”]
package javabeat.net.reflection;

import java.lang.reflect.Constructor;

/**
* Get Constructors using Reflection
*
* @author krishna
*
*/
public class JavaBeatReflectionExample {
private JavaBeatReflectionExample() {
System.out.println("Default Constructor Called");
}

public JavaBeatReflectionExample(int i) {
System.out.println("One Parameter Constructor Called");
}

public static void main(String[] args) throws Exception {
JavaBeatReflectionExample reflectionExample = new JavaBeatReflectionExample();
// Get all the constructors
Constructor cons[] = reflectionExample.getClass().getDeclaredConstructors();
cons[0].newInstance();
cons[1].newInstance(9);
}
}
[/code]

Output

[code]
Default Constructor Called
Default Constructor Called
One Parameter Constructor Called
[/code]

Filed Under: Java Tagged With: Core Java, Java Reflection

About Krishna Srinivasan

He is Founder and Chief Editor of JavaBeat. He has more than 8+ years of experience on developing Web applications. He writes about Spring, DOJO, JSF, Hibernate and many other emerging technologies in this blog.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Follow Us

  • Facebook
  • Pinterest

As a participant in the Amazon Services LLC Associates Program, this site may earn from qualifying purchases. We may also earn commissions on purchases from other retail websites.

JavaBeat

FEATURED TUTORIALS

Answered: Using Java to Convert Int to String

What is new in Java 6.0 Collections API?

The Java 6.0 Compiler API

Copyright © by JavaBeat · All rights reserved