Class getDeclaredConstructors() method in Java with Examples (original) (raw)

Last Updated : 05 Jun, 2021

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 parameter.
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:

Java

import java.util.*;

public class Test {

`` public static void main(String[] args)

`` throws ClassNotFoundException

`` {

`` Class myClass = Class.forName( "Test" );

`` System.out.println( "Class represented by myClass: "

`` + myClass.toString());

`` System.out.println(

`` "DeclaredConstructors of myClass: "

`` + Arrays.toString(

`` myClass.getDeclaredConstructors()));

`` }

}

Output:

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

Example 2:

Java

import java.util.*;

class Main {

`` public Object obj;

`` private Main()

`` {

`` class Arr {

`` };

`` obj = new Arr();

`` }

`` public static void main(String[] args)

`` throws ClassNotFoundException

`` {

`` Class myClass = Class.forName( "Main" );

`` System.out.println( "Class represented by myClass: "

`` + myClass.toString());

`` System.out.println(

`` "DeclaredConstructors of myClass: "

`` + Arrays.toString(

`` myClass.getDeclaredConstructors()));

`` }

}

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–

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