title: Spark DataFrame groupBy
body: <p>I have Spark Java that looked like this. Code pulls data from oracle table using JDBC and displays the groupby output.</p>
  
  <pre><code>DataFrame jdbcDF = sqlContext.read().format("jdbc").options(options).load();
  jdbcDF.show();   
  jdbcDF.groupBy("VA_HOSTNAME").count().show();
  
  Long ll = jdbcDF.count();
  System.out.println("ll="+ll);
  </code></pre>
  
  <p>When I ran the code,     <code>jdbcDF.show();</code>   is working, whereas the <code>groupBy</code> and count are not printing anything and no errors were thrown.</p>
  
  <p>My column name is correct. I tried by printing that column and it worked, but when <code>groupBy</code> it's not working.</p>
  
  <p>Can someone help me with <code>DataFrame</code> output? I am using spark 1.6.3.</p>