title: System property is always null in maven project
body: <p>My utility class  </p>
  
  <pre><code>Properties prop = new Properties();
          ClassLoader loader = Thread.currentThread().getContextClassLoader();
          String profile = System.getProperty("env");
          //InputStream in = loader.getResourceAsStream(fileName + ".properties");
          InputStream in = loader.getResourceAsStream(fileName + "_" + profile + ".properties");
  </code></pre>
  
  <p>always return null.</p>
  
  <p>I did add properties-maven-plugin in pom</p>
  
  <pre><code>&lt;plugin&gt;
              &lt;groupId&gt;org.codehaus.mojo&lt;/groupId&gt;
              &lt;artifactId&gt;properties-maven-plugin&lt;/artifactId&gt;
              &lt;version&gt;1.0.0&lt;/version&gt;
              &lt;executions&gt;
                  &lt;execution&gt;
                      &lt;goals&gt;
                          &lt;goal&gt;set-system-properties&lt;/goal&gt;
                      &lt;/goals&gt;
                      &lt;configuration&gt;
                          &lt;properties&gt;
                              &lt;property&gt;
                                  &lt;name&gt;env&lt;/name&gt;
                                  &lt;value&gt;prod&lt;/value&gt;
                              &lt;/property&gt;
                          &lt;/properties&gt;
                      &lt;/configuration&gt;
                  &lt;/execution&gt;
              &lt;/executions&gt;
          &lt;/plugin&gt;
  </code></pre>
  
  <p>but still no luck in getting the property value in util class.</p>