title: How to use property as a variable?
body: <p>For example I have property:  <code>project.password.time=123456</code></p>
  
  <p>Then I want to use it in some class as a variable.</p>
  
  <p>For example, <code>Long time = {my property}</code></p>
  
  <p>This doesn't work: (java.lang.NumberFormatException: null)</p>
  
  <pre><code>Long time = Long.valueOf(System.getProperty("project.password.time"))  
  </code></pre>
  
  <p>How can I do it?</p>