title: Handle null values in spring expression language
body: <p>I have the following code using spring expression language:</p>
  
  <pre><code>StandardEvaluationContext stdContext = new StandardEvaluationContext();
  stdContext.setVariable("emp", filterInputData); 
  ExpressionParser parser = new SpelExpressionParser();     
  parser.parseExpression("#emp.?[name.toLowerCase().contains('Hari')]").getValue(stdContext);
  </code></pre>
  
  <p>where <em>emp</em> is the name of the bean. Here the name can be null and when calling <code>name.toLowerCase()</code> I am getting a nullpointer exception. How to handle the null values in this scenario? I need to call <code>toLowercase()</code> for only non-null values.</p>