title: Java TypesafeConfig generate config key and read its value
body: <p>I am using Typesafeconfig in my project. I want to read the config and generates a value, which is again a config key and I want to read this config key's value.</p>
  
  <p>Example:</p>
  
  <pre><code>fs {
    city = ${CITY}
    number = ${NUMBER}
    cityNumberKey = ${CITY}"_"${NUMBER}
    cityNumber = ${fs.cityNumberKey}
  }
  </code></pre>
  
  <p>In above example, the value of cityNumber is same as cityNumberKey. What I am actually trying to do is to read the value of cityNumberKey config.</p>
  
  <p>Example, let's say if <code>city</code> is <code>Delhi</code> and <code>Number</code> is <code>31</code>, then I want to read the value of config <code>Delhi_31</code> in <code>cityNumber</code> object.</p>
  
  <p>Appreciate any example for the same.</p>
  
  <p>Thanks</p>