JAVA EE: How to access the constructors of a class using Java Reflection

Thursday 26 October 2017

How to access the constructors of a class using Java Reflection | Reflection in java

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ReflectionDemo.java

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

/**
 * 
 * We can access the constructors of a class.
 *
 */
public class ReflectionDemo
{
    public static void main(String[] args)
    {

        Class<ArrayList> classObj = ArrayList.class;

        /*
         * Returns:the array of Constructor objects representing the public
         * constructors of this class
         */

        Constructor<?>[] constructorArray = classObj.getConstructors();

        for (Constructor constructor : constructorArray)
        {
            System.out.println(constructor);
            System.out.println("Name = "+constructor.getName());
            System.out.println("ParameterCount = "+constructor.getParameterCount());
            System.out.println("-----------------------------");
        }

    }

}

Output

public java.util.ArrayList(java.util.Collection)
Name = java.util.ArrayList
ParameterCount = 1
-----------------------------
public java.util.ArrayList()
Name = java.util.ArrayList
ParameterCount = 0
-----------------------------
public java.util.ArrayList(int)
Name = java.util.ArrayList
ParameterCount = 1
-----------------------------