Java Reflection Constructor Invoke invokePrivateConstructor(Class clazz)

Description

Utility method for Unit tests to invoke private constructors

License

Open Source License

Parameter

Parameter	Description
clazz	The class we're gonig to invoke the constructor on

Return

An instance of the class

Declaration

public static Object invokePrivateConstructor(Class<?> clazz) 

Method Source Code

//package com.java2s;
/*/*from   w  w w  .j a  v  a 2 s.c  o m*/
 * Copyright 2014 (C) Tom Parker <thpr@users.sourceforge.net>
 * 
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

public class Main {
    /**
     * Utility method for Unit tests to invoke private constructors
     * 
     * @param clazz The class we're gonig to invoke the constructor on
     * @return An instance of the class
     */
    public static Object invokePrivateConstructor(Class<?> clazz) {
        Constructor<?> constructor = null;
        try {
            constructor = clazz.getDeclaredConstructor();
        } catch (NoSuchMethodException e) {
            System.err.println("Constructor for [" + clazz.getName()
                    + "] does not exist");
        }

        constructor.setAccessible(true);
        Object instance = null;

        try {
            instance = constructor.newInstance();
        } catch (InvocationTargetException | InstantiationException ite) {
            System.err.println("Instance creation failed with ["
                    + ite.getCause() + "]");
        } catch (IllegalAccessException iae) {
            System.err
                    .println("Instance creation failed due to access violation.");
        }

        return instance;
    }
}

Related

1. invokeConstructor(String className, Class[] paramTypes, Object[] paramValues)
2. invokeConstructor(String className, Object... arguments)
3. invokeConstructorOrFail(Constructor constructor, Object... args)
4. invokeCtor(Constructor ctor, String str)
5. invokeExactConstructor(Class klass, Object arg)
6. invokePrivateConstructor(Class classType)
7. invokePrivateConstructor(Class clazz)
8. invokeReflectConstruct(String className, Object[] parameter, Class[] args)