<f:form action="#" method="post">
    <f:hidden name="id" />
</f:form>

<form action="#" method="post">
    <f:hidden name="id" />
</form>

public class HiddenTag extends SimpleTagSupport{

    @Override
public void doTag() throws JspException, IOException {
    try {
    /*
     * Start Velocity
     * */
    VelocityEngine ve = new VelocityEngine();
    ve.setProperty(RuntimeConstants.RESOURCE_LOADER, "class");
    ve.setProperty("class.resource.loader.class", ClasspathResourceLoader.class.getName());
    ve.init();

    VelocityContext context = createContext();

    StringWriter writer = new StringWriter();


    /*
     * Get Open Tag
     * */
    Template template = ve.getTemplate("form.vm");
    template.merge(context, writer);


    /*
     * Get Body Tag
     *
     * I THINK THE ERROR IS HERE
     *
     * */
    JspFragment body = getJspBody();
    body.invoke(writer);
    /**/

    /*
     * Get Close Tag
     * */
    template = ve.getTemplate("form-close.vm");
    template.merge(context, writer);

    getJspContext().getOut().println(writer.getBuffer());

} catch (Exception e) {
    e.printStackTrace();
    }
}

}

<dependency>
            <groupId>org.apache.velocity</groupId>
            <artifactId>velocity</artifactId>
            <version>1.6.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.velocity</groupId>
            <artifactId>velocity-tools</artifactId>
            <version>2.0</version>
        </dependency>