title: Should "null" ever a valid value for a property?
body: <p>I have a key=value property, which is then written to file. If a key exists but the value is empty or null, it is saved as, key="". Now, could the literal string "null" ever be a valid property value for a key? Which got asked in my code review but I feel like it would be bad practice to treat it as valid, as the system treats empty strings as null values.</p>
  
  <p>At the moment, the property is formatted as an empty string if it is null or "null"</p>
  
  <pre><code>if (key != null &amp;&amp; !key.trim().isEmpty() &amp;&amp; key.startsWith("-D")) {    
      if (value == null || value.equals("null")) {
          value = "";
  }
  //Other code
  </code></pre>
  
  <p>The value is appended onto a formatted key to be written to a file.</p>