How do I get constructors of a class object?

By Wayan in Reflection 0 Comment

Below is an example that showing you how to get constructors of a class object. In the code below we get the constructors by calling the Class.getDeclaredConstructors() or the Class.getConstructor(Class[]) method.

package org.kodejava.lang.reflect;

import java.lang.reflect.Constructor;

public class GetConstructors {
    public static void main(String[] args) {
        Class<String> clazz = String.class;

        // Get all declared constructors and iterate the constructors to get their
        // name and parameter types.
        Constructor<?>[] constructors = clazz.getDeclaredConstructors();
        for (Constructor<?> constructor : constructors) {
            String name = constructor.getName();
            System.out.println("Constructor name= " + name);

            Class<?>[] parameterTypes = constructor.getParameterTypes();
            for (Class<?> c : parameterTypes) {
                System.out.println("Param type name = " + c.getName());
            }
            System.out.println("----------------------------------------");
        }

        // Getting a specific constructor of the java.lang.String
        try {
            Constructor<String> constructor = String.class.getConstructor(String.class);
            System.out.println("Constructor     = " + constructor.getName());
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
    }
}
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