How to Combine StringWriter with template in java

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import java.io.StringWriter;
import java.io.Writer;

import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;

public class HelloWorldWithVariable {

public static void main(String[] args) throws Exception {
Velocity.init();

Template template = Velocity.getTemplate("src/HelloWorldWithVariable.vm");

VelocityContext context = new VelocityContext();

context.put("name", "Joe Yin");

Writer writer = new StringWriter();
template.merge(context, writer);

System.out.println(writer.toString());
}
}
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Hello $name!