code: private void addModificationDateColumn() {
  
          addColumn(CmsHistoryMessages.columnModificationDate(), 190, new TextColumn<CmsHistoryResourceBean>() {
  
              @Override
              public String getValue(CmsHistoryResourceBean historyRes) {
  
                  return historyRes.getModificationDate().getDateText();
              }
          });
      }
docs: Adds a table column.<p>