title: how spring property resolver works?
body: <p>I have property place holder in my spring context.xml file </p>
  
  <pre><code>&lt;bean id="propertyConfigurer" class="com.techpleiad.poc.RMCPropertyUtil"&gt;
          &lt;property name="basenames" value="file:${config.file.dir}/prop_application" /&gt;
          &lt;property name="defaultEncoding" value="UTF-8" /&gt;
          &lt;property name="cacheSeconds" value="30"&gt;&lt;/property&gt;
      &lt;/bean&gt;
  </code></pre>
  
  <p>and this property '<em>config.file.dir</em>' is not getting resolved.</p>
  
  <p>'config.file.dir' is the <strong>environment variable</strong> and when i debug the code and check for the basename the file path comes as it is.. '<em>{config.file.dir}/prop_application</em>'</p>
  
  <p>I need to know what spring code/classes are involved in resolving such properties. 
  How i could debug and resolve this problem?</p>