Class getDeclaredConstructors() method in Java with Examples

The getDeclaredConstructors() method of java.lang.Class class is used to get the constructors of this class, which are the constructors that are private, public, protected or default. The method returns the constructors of this class in the form of array of Constructor objects.

Syntax:

public Constructor[] getDeclaredConstructors()
                      throws SecurityException

Parameter: This method does not accept any paramter.

Return Value: This method returns the constructors of this class in the form of an array of Constructor objects.

Exception This method throws SecurityException if a security manager is present and the security conditions are not met.



Below programs demonstrate the getDeclaredConstructors() method.

Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java program to demonstrate
// getDeclaredConstructors() method
  
import java.util.*;
  
public class Test {
    public static void main(String[] args)
        throws ClassNotFoundException
    {
  
        // returns the Class object for this class
        Class myClass = Class.forName("Test");
  
        System.out.println("Class represented by myClass: "
                           + myClass.toString());
  
        // Get the constructors of myClass
        // using getDeclaredConstructors() method
        System.out.println(
            "DeclaredConstructors of myClass: "
            + Arrays.toString(
                  myClass.getDeclaredConstructors()));
    }
}

chevron_right


Output:

Class represented by myClass: class Test
DeclaredConstructors of myClass: [public Test()]

Example 2:

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java program to demonstrate 
//getDeclaredConstructors() method
  
import java.util.*;
  
class Main {
  
    public Object obj;
  
    private Main()
    {
  
        class Arr {
        };
  
        obj = new Arr();
    }
  
    public static void main(String[] args)
        throws ClassNotFoundException
    {
        // returns the Class object for this class
        Class myClass = Class.forName("Main");
  
        System.out.println("Class represented by myClass: "
                           + myClass.toString());
  
        // Get the constructors of myClass
        // using getDeclaredConstructors() method
        System.out.println(
            "DeclaredConstructors of myClass: "
            + Arrays.toString(
                  myClass.getDeclaredConstructors()));
    }
}

chevron_right


Output:

Class represented by myClass: class Main
DeclaredConstructors of myClass: [private Main()]

Reference: https://docs.oracle.com/javase/9/docs/api/java/lang/Class.html#getDeclaredConstructors–

Attention reader! Don’t stop learning now. Get hold of all the important Java and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready.




My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.