How to use an existing Log4j Categeory as the Velocity logging target in java

/*
* Copyright 2000-2001,2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
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*/

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Category;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.runtime.RuntimeConstants;


/**
* Simple example class to show how to use an existing Log4j Categeory
* as the Velocity logging target.
*
* @author Geir Magnusson Jr.
* @version $Id: Log4jCategoryExample.java,v 1.1.8.1 2004/03/04 00:18:29 geirm Exp $
*/
public class Log4jCategoryExample
{
public static String CATEGORY_NAME = "velexample";

public static void main( String args[] )
throws Exception
{
/*
* configure log4j to log to console
*/

BasicConfigurator.configure();

Category log = Category.getInstance( CATEGORY_NAME );

log.info("Hello from Log4jCategoryExample - ready to start velocity");

/*
* now create a new VelocityEngine instance, and
* configure it to use the category
*/

VelocityEngine ve = new VelocityEngine();

ve.setProperty( RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS,
"org.apache.velocity.runtime.log.SimpleLog4JLogSystem" );

ve.setProperty("runtime.log.logsystem.log4j.category", CATEGORY_NAME);

ve.init();

log.info("this should follow the initialization output from velocity");
}
}