Logger error with multiple Velocity engines

[Andrea Vaccaro]

Hello,
we have found out that if you instance and init multiple engines, under some 
circumstances that are not yet clear, there is an error on the log4j logger.

For example the following code:

public static void main(String[] args) throws Exception
{
       VelocityEngine[] engines = new VelocityEngine[4];
        
        for (int i = 0; i < engines.length; i++)
        {
            VelocityEngine engine = new VelocityEngine();
            engine.setProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, 
"C:\\temp");
            engine.init();
        }
}

will generate 141 lines of the following error:

log4j:ERROR Attempted to append to closed appender named [null].

Debugging Velocity source code we noticed that all the engines add an appender 
to the same shared logger and sometime a null appender is added.
We are currently using Velocity 1.4 and Log4J 1.2.9.

Thanks in advance,
Andrea and Giannandrea