title: Spring evaluation language (SpEL) not throw exception when accessing invalid key in map
body: <p>I am new to SpEL and below is a sample workable test that I used for testing.</p>
  
  <pre><code>public static void main(String[] args) {
  
      Map&lt;String,String&gt; dictMap = new HashMap&lt;&gt;();
      dictMap.put("key", "value");
      Map&lt;String, Object&gt; rootObj = new HashMap&lt;&gt;();
      rootObj.put("d", dictMap);
  
      ExpressionParser parser = new SpelExpressionParser();
      Expression exp = parser.parseExpression("['d']['wrongkey']");
      String msg = (String) exp.getValue(new StandardEvaluationContext(rootObj), String.class);
      System.out.println(msg);
  }
  </code></pre>
  
  <p>I expected that the expression should throw exception because there is no key named "wrongkey" in dictMap context. However, it print "null".</p>
  
  <p>Is there any setting that I can use to force the expression evaluation throw exception?</p>
  
  <p>Thank you</p>