title: JTable DefaultCellRenderer doesn't work on BigDecimal Type when I set Object.class
body: <p>It is weird that I set my JTable cell renderer like this:</p>
  
  <pre><code>setDefaultRenderer(Object.class, new MyTableRenderer());
  </code></pre>
  
  <p>My table renderer works like this:</p>
  
  <pre><code>class MyTableRenderer extends DefaultTableCellRenderer {
      public Component getTableCellRendererComponent(JTable table, Object value,
                      boolean isSelected, boolean hasFocus, int row, int column) {
          Component comp = super.getTableCellRendererComponent(table, value,
                                              isSelected, hasFocus, row, column);
          Font font = comp.getFont();
  
          if (table.getModel().getValueAt(row, 0).equals(BUY)) {
              comp.setFont(font.deriveFont(Font.BOLD));
              comp.setForeground(BUY_COLOR);
          }
          else {
              comp.setFont(font.deriveFont(Font.BOLD));
              comp.setForeground(SELL_COLOR);
          }
          return comp;
      }
  }
  </code></pre>
  
  <p>But it turns out, it didin't apply those columns that have type "BigDecimal", Other String fields are all working fine.</p>
  
  <p>And then, I add one more line:</p>
  
  <pre><code>setDefaultRenderer(BigDecimal.class, new MyTableRenderer());
  </code></pre>
  
  <p>Then everything just work fine.
  Why it is like this?</p>