// Check if the cell (1,2) is completely visible
    int rowIndex = 1;
    int vColIndex = 2;
    isCellVisible(table, rowIndex, vColIndex);
    
    // Assumes table is contained in a JScrollPane. Returns true iff the
    // cell (rowIndex, vColIndex) is completely visible within the viewport.
    public boolean isCellVisible(JTable table, int rowIndex, int vColIndex) {
        if (!(table.getParent() instanceof JViewport)) {
            return false;
        }
        JViewport viewport = (JViewport)table.getParent();
    
        // This rectangle is relative to the table where the
        // northwest corner of cell (0,0) is always (0,0)
        Rectangle rect = table.getCellRect(rowIndex, vColIndex, true);
    
        // The location of the viewport relative to the table
        Point pt = viewport.getViewPosition();
    
        // Translate the cell location so that it is relative
        // to the view, assuming the northwest corner of the
        // view is (0,0)
        rect.setLocation(rect.x-pt.x, rect.y-pt.y);
    
        // Check if view completely contains cell
        return new Rectangle(viewport.getExtentSize()).contains(rect);
    }