title: How to apply several QualifierFilter to a row in HBase
body: <p>we would like to filter a scan on a HBase table with two QualifierFilters.
  Means we would like to only get the rows of the table which do have a certain column 'col_A' <strong>AND</strong> (!) a certain other column 'col_B'.</p>
  
  <p>Our current approach looks like this:</p>
  
  <pre><code>FilterList filterList = new FilterList(FilterList.Operator.MUST_PASS_ALL);
  Filter filter1 = new QualifierFilter(CompareOp.EQUAL, new BinaryComparator("col_A".getBytes()));
  filterList.addFilter(filter1);
  Filter filter2 = new QualifierFilter(CompareOp.EQUAL, new BinaryComparator("col_B".getBytes()));
  filterList.addFilter(filter2);
  
  Scan scan = new Scan();
  scan.setFilter(filterList);
  ... 
  </code></pre>
  
  <p>The ResultScanner does not return any results from this scan although there are several rows in the HBase table which do have both columns 'col_A' and 'col_B'.</p>
  
  <p>If we only apply filter1 to the scan everything works fine an we do get all the rows which have 'col_A'. 
  If we only apply filter2 to the scan it is the same. We do get all rows which have 'col_B'.</p>
  
  <p>Only if we combine these two filters we do not get any results.</p>
  
  <p>What would be the right way to get only the rows from the table which do have col_A AND col_B?</p>