Create a new Maven project as follows:

Edit pom.xml:

<project>

  <modelVersion>4.0.0</modelVersion>

  <groupId>com.acme.samples</groupId>

  <artifactId>hello-portlet</artifactId>

  <version>1.0</version>

  <packaging>war</packaging>

  <build>

    <finalName>prp-portlet</finalName>

  </build>



  <dependencies>

    <dependency>

      <groupId>javax.portlet</groupId>

      <artifactId>portlet-api</artifactId>

      <version>2.0</version>

      <scope>provided</scope>

    </dependency>

  </dependencies>

</project>

Edit web.xml:

<web-app>

  <display-name>prp-portlet</display-name>

</web-app>

Edit portlet.xml:

<portlet-app version="2.0" xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd"

  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  xsi:schemaLocation="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd">

  <portlet>

    <portlet-name>Sharing-PRP-Portlet</portlet-name>

    <portlet-class>com.acme.samples.SharingPRPPortlet</portlet-class>

    <supports>

      <mime-type>text/html</mime-type>

    </supports>

    <portlet-info>

      <title>Sharing-PRP-Portlet</title>

    </portlet-info>

    <supported-public-render-parameter>current_time</supported-public-render-parameter>

  </portlet>

  <portlet>

    <portlet-name>Consuming-PRP-Portlet</portlet-name>

    <portlet-class>com.acme.samples.ConsumingPRPPortlet</portlet-class>

    <supports>

      <mime-type>text/html</mime-type>

    </supports>

    <portlet-info>

      <title>Consuming-PRP-Portlet</title>

    </portlet-info>

    <supported-public-render-parameter>current_time</supported-public-render-parameter>

  </portlet>

  <public-render-parameter>

    <identifier>current_time</identifier>

    <name>current_time</name>

  </public-render-parameter>

</portlet-app>

Edit SharingPRPPortlet.java:

package com.acme.samples;


import java.io.IOException;

import java.io.PrintWriter;

import java.util.Date;


import javax.portlet.GenericPortlet;

import javax.portlet.RenderRequest;

import javax.portlet.RenderResponse;

import javax.portlet.PortletException;

import javax.portlet.ActionRequest;

import javax.portlet.ActionResponse;

import javax.portlet.PortletURL;


public class SharingPRPPortlet extends GenericPortlet {


  @Override

  public void processAction(ActionRequest request, ActionResponse response) throws IOException, PortletException {

    response.setRenderParameter("current_time", new Date(System.currentTimeMillis()).toString());

  }


  @Override

  public void doView(RenderRequest request, RenderResponse response) throws IOException, PortletException {

    PortletURL actionURL = response.createActionURL();

    PrintWriter w = response.getWriter();

    w.write("<p>Click <a href=\"" + actionURL.toString() + "\">here</a> to execute processAction()</p>");

    w.write("<span>" + request.getParameter("current_time") + "</span>");

    w.close();

  }

}

Edit ConsumingPRPPortlet.java:

package com.acme.samples;


import java.io.IOException;

import java.io.PrintWriter;

import java.util.Map;


import javax.portlet.GenericPortlet;

import javax.portlet.RenderRequest;

import javax.portlet.RenderResponse;

import javax.portlet.PortletException;

import javax.portlet.ActionRequest;

import javax.portlet.ActionResponse;


public class ConsumingPRPPortlet extends GenericPortlet {


  @Override

  public void doView(RenderRequest request, RenderResponse response) throws IOException, PortletException {

    Map<String, String[]> paramNames = request.getPublicParameterMap();

    PrintWriter w = response.getWriter();

    for (String name : paramNames.keySet()) {

      String value = request.getParameter(name);

      w.write("<p>" + "*<b>" + name + "</b>: " + value + "</p>");

    }

    w.close();

  }

}