Is Velocity thread safe?

[Jayesh A Lalwani]

We have a Velocity Helper class that wraps Velocity engine for processing templates. The helper method is basically this

public static void processTemplate(Reader reader, Map<?, ?> context,
                                       Writer writer)
                                throws Exception,
                                       ParseErrorException,
                                       MethodInvocationException,
                                       ResourceNotFoundException,
                                       IOException {
        // Separate instance
        VelocityEngine ve = new VelocityEngine();

        // initialize velocity context
        VelocityContext velocityContext = new VelocityContext(context);

        // set the null logger
        ve.setProperty(
            RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS,
            "org.apache.velocity.runtime.log.NullLogSystem");

        // initialize velocity with default properties
        ve.init();

        // process the template
        ve.evaluate(
            velocityContext,
            writer,
            "[Template]",
            new BufferedReader(reader));
    }

The thing is VelocityEngine is not really a lightweightt object, and I wanted to see if we can avoid creating an engine eveytime. In my thread dumps I see it loading and parsing some resources from classpath. This creates memory issues in JBoss 5.1 because VelocityEngine ends up calling CFS which has memory leaks. That is a whole another issue of course, but frequent creation of VelocityEngine instances excaberates the JBoss memory leaks. We are going to explode our war so we don;t use VFS.

So, I was wondering if I can just have one instance of VelocityEngine? Is it thread safe?