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 * Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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// NewInstance.java - create a new instance of a class by name.
// http://www.saxproject.org
// Written by Edwin Goei, edwingo@apache.org
// and by David Brownell, dbrownell@users.sourceforge.net
// NO WARRANTY!  This class is in the Public Domain.
// $Id: NewInstance.java,v 1.2 2005/06/10 03:50:50 jeffsuttor Exp $

package org.xml.sax.helpers;

import java.lang.reflect.InvocationTargetException;
import java.util.Objects;

Create a new instance of a class by name.

This module, both source code and documentation, is in the
Public Domain, and comes with NO WARRANTY.
See http://www.saxproject.org
for further information.

This class contains a static method for creating an instance of a
class from an explicit class name.  It tries to use the thread's context
ClassLoader if possible and falls back to using
Class.forName(String).
This code is designed to compile and run on JDK version 1.1 and later
including versions of Java 2.
Author:
Edwin Goei, David Brownell
Version:
2.0.1 (sax2r2)/**
 * Create a new instance of a class by name.
 *
 * <blockquote>
 * <em>This module, both source code and documentation, is in the
 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
 * for further information.
 * </blockquote>
 *
 * <p>This class contains a static method for creating an instance of a
 * class from an explicit class name.  It tries to use the thread's context
 * ClassLoader if possible and falls back to using
 * Class.forName(String).</p>
 *
 * <p>This code is designed to compile and run on JDK version 1.1 and later
 * including versions of Java 2.</p>
 *
 * @author Edwin Goei, David Brownell
 * @version 2.0.1 (sax2r2)
 */
class NewInstance {
    private static final String DEFAULT_PACKAGE = "com.sun.org.apache.xerces.internal";
    private static final String DEFAULT_CLASS = "com.sun.org.apache.xerces.internal.parsers.SAXParser";
    
Creates a new instance of the specified class name
Package private so this code is not exposed at the API level.
/**
     * Creates a new instance of the specified class name
     *
     * Package private so this code is not exposed at the API level.
     */
    static <T> T newInstance (Class<T> type, ClassLoader loader, String clsName)
        throws ClassNotFoundException, IllegalAccessException,
            InstantiationException
    {
        ClassLoader classLoader = Objects.requireNonNull(loader);
        String className = Objects.requireNonNull(clsName);

        // Instantiate directly for the SAX default parser
        if (className.equals(DEFAULT_CLASS)) {
            return type.cast(new com.sun.org.apache.xerces.internal.parsers.SAXParser());
        }

        // make sure we have access to restricted packages
        boolean internal = false;
        if (System.getSecurityManager() != null) {
            if (className != null && className.startsWith(DEFAULT_PACKAGE)) {
                internal = true;
            }
        }

        Class<?> driverClass;
        if (classLoader == null || internal) {
            driverClass = Class.forName(className);
        } else {
            driverClass = classLoader.loadClass(className);
        }

        try {
            return type.cast(driverClass.getConstructor().newInstance());
        } catch (NoSuchMethodException | SecurityException | InvocationTargetException ex) {
            throw new InstantiationException(ex.getMessage());
        }
    }

}