Java Class getDeclaredConstructors() Method

The getDeclaredConstructors() method of java Class class returns an array of constructor objects representing all the constructors defined in this class object. If no constructor is declared, then it returns an array of length 0.

Syntax

Parameter

Returns

An array of constructor object.

Throws

SecurityException

Example 1

import java.lang.reflect.*;
public class ClassgetDeclaredConstructorsExample1 {
   public static void main(String[] args) {
      ClassgetDeclaredConstructorsExample1  obj = new ClassgetDeclaredConstructorsExample1();
      Class cls = obj.getClass();

      Constructor[] cnstrct = cls.getDeclaredConstructors();
      for(int i = 0; i < cnstrct.length; i++) {
         System.out.println("Constructor  : " +(i+1)+ " =  " + cnstrct[i].toString());
      }
   }

   private ClassgetDeclaredConstructorsExample1() {
      System.out.println("no argument constructor");
   }

   public ClassgetDeclaredConstructorsExample1(Double dbl, Long lng) {
      this.dbl = dbl;
      this.lng = lng;
   }
   Double dbl = new Double(3.9d);
   Long lng = new Long(7687);
} 

Test it Now

Output:

no argument constructor
Constructor  : 1 =  private ClassgetDeclaredConstructorsExample1()
Constructor  : 2 =  public ClassgetDeclaredConstructorsExample1(java.lang.Double,java.lang.Long)

Example 2

import java.lang.reflect.Constructor;
import java.util.Arrays;

public class ClassgetDeclaredConstructorsExample2 {
    public ClassgetDeclaredConstructorsExample2 () {
    }

    public ClassgetDeclaredConstructorsExample2(int intgr) {
    }

    private ClassgetDeclaredConstructorsExample2(String str) {
    }

    public static void main(String... args) {
        Constructor<?>[] constrct = ClassgetDeclaredConstructorsExample2.class.getDeclaredConstructors();
        Arrays.stream(constrct).forEach(System.out::println);

    }
}

Test it Now

Output:

private ClassgetDeclaredConstructorsExample2(java.lang.String)
public ClassgetDeclaredConstructorsExample2(int)
public ClassgetDeclaredConstructorsExample2()

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