a bug of JTable.columnMoved method

Question

javax.swing.JTable has a bug, if we sort the table while a null valued cell is editing, and whose column class does not have a constructor with "new Object[] { new String() }" parameter, eg. Long.class, the JTable will throw an exception. I think that because javax.swing.JTable tries to remove the cell editor twice; So I plan to override the JTable.columnMoved method as: ``` @Override public void columnMoved(TableColumnModelEvent e) { if (isEditing() && !getCellEditor().stopCellEditing()) { if(getCellEditor() != null) { // In javax.swing.JTable, no this check point getCellEditor().cancelCellEditing(); } } repaint(); } ``` I felt that's not good enough, since it's not friendly for code readers, they may know JTable well, and do not like my sub classes like this. Is there a better solution? Thanks a lot. When running the following codes, double click one cell (do not input anything) and then click the header, the exception will show up. ``` public class NewJFrame extends javax.swing.JFr…

Accepted Answer

I can reproduce the issue with the code you provided. I blame the `JTable#stopCellEditing` implementation

```
    public boolean stopCellEditing() {
        String s = (String)super.getCellEditorValue();
        // Here we are dealing with the case where a user
        // has deleted the string value in a cell, possibly
        // after a failed validation. Return null, so that
        // they have the option to replace the value with
        // null or use escape to restore the original.
        // For Strings, return "" for backward compatibility.
        if ("".equals(s)) {
            if (constructor.getDeclaringClass() == String.class) {
                value = s;
            }
            super.stopCellEditing();
        }

try {
            value = constructor.newInstance(new Object[]{s});
        }
        catch (Exception e) {
            ((JComponent)getComponent()).setBorder(new LineBorder(Color.red));
            return false;
        }
        return super.stopCellEditing();
    }
```

You enter the first if, where `super.stopCellEditing` is called. The return value of this call is ignored. Then the `newInstance` call throws an exception, which is catched but then `false` is returned, no matter what the return value was of `super.stopCellEditing`. This sounds incorrect to me. I would log the bug with Oracle with the code you provided

a bug of JTable.columnMoved method

Solution

Problem