Cannot load properties file when unit test

[greenlaw110]

Hi

I have a properties file need to be loaded to do unit test. I put the file in the 
${maven.src.dir}/test, I write a maven.xml file as follows:
<project
  xmlns:j="jelly:core"
  xmlns:m="maven"
  xmlns:u="jelly:util"
  default="java:jar">
  <preGoal name="test:test">
    <copy 
      file="${maven.src.dir}/test/jport.properties"
      todir="${maven.test.dest}"
 />
  </preGoal>
</project>

But I found I cannot load the properties file using the following code in my unit 
test:
  Properties conf = null;
  try
  {
   InputStream is = ClassLoader.getSystemResourceAsStream("xxx.properties"); 
   if (null != is)
   {
    conf = new Properties();
    conf.load(is); 
   }
   return conf;
  }
  catch(IOException e)
  {
   return null;
  }

Can u tell me where I am wrong? TIA