title: Get method of an hashmap with key as another hashmap always returns null values
body: <p>I have two hashmaps. Each of those have keys as other hashmaps like the one below.</p>
  
  <pre><code>Map&lt;Map&lt;String, Object&gt;, Map&lt;String, Object&gt;&gt;
  </code></pre>
  
  <p>This map gets filled from values of a DB2 database query output. I have noticed that even when I have two such hashmaps and if I try to retrieve the value for a hashmap key, it always returns me null. I have checked by adding all the needed variables in watch window. Everything looks good to me.</p>
  
  <p>Small snippet of my code.</p>
  
  <pre><code>mapTransactionNumberTranIds
                  .put(inputMessageDbRecord
                          .get(i)
                          .get(prop.getProperty(
                                  BloombergConstants.INPUT_BBR_TRANS_NO).toString())
                          .toString(),
                          inputMessageDbRecord
                                  .get(i)
                                  .get(prop.getProperty(
                                          BloombergConstants.TRAN_ID)
                                          .toString()).toString());
  </code></pre>
  
  <p>Note:
      inputMessageDbRecord is of type <code>List&lt;Map&lt;String, Object&gt;&gt;</code> and mapTransactionNumberTranIds is of type <code>Map&lt;Map&lt;String, Object&gt;, Map&lt;String, Object&gt;&gt;</code></p>