title: Reading empty list of ids from properties file and initialise as empty collection
body: <p>I have the following property in properties file:</p>
  
  <pre><code>target.specifiedIds=
  </code></pre>
  
  <p>My model has constructor something like this:</p>
  
  <pre><code>   public ConnectionInfo(String type, Set&lt;String&gt; ids) {
          this.type= type;
          this.ids= ids;
      }
  </code></pre>
  
  <p>My spring file initialises constructor as follows:</p>
  
  <pre><code>&lt;bean id="something" class="something.ConnectionInfo"&gt;
          &lt;constructor-arg value="${report.type}"/&gt;
          &lt;constructor-arg value="#{'${target.specifiedIds}'.split(',')}"/&gt;
  </code></pre>
  
  <p>In the property file, I can get Ids defined or ids not defined in which case my application will handle all possible ids available</p>
  
  <pre><code>target.specifiedIds= 54, 88
  target.specifiedIds=
  </code></pre>
  
  <p>In the second case, when there is no id's defined, the above would add an element with empty string to the  <code>Set</code> collection even though nothing has been specified. How can I prevent this <code>SPEL</code>? Or is there a better alternative? </p>
  
  <pre><code>if (!connection.getIds().isEmpty()) {
          Set&lt;String&gt; acceptedIds = connection.getIds();
          //do something
      }
  </code></pre>
  
  <p>The above should return empty when no ids specified? How can I handle this? </p>