Unfortunately, there is no setToolTipText() method for cells in a JTable component. For a cell to show a tool tip, the renderer for that cell must set the tool tip text on the returned component. See e928 Creating a Custom Cell Renderer in a JTable Component for an example of a renderer that sets a tool tip.
If you cannot modify the renderer, you can override the table's prepareRenderer() method and explicitly set the tool tip on the returned component.
// This table displays a tool tip text based on the string
// representation of the cell value
JTable table = new JTable() {
public Component prepareRenderer(TableCellRenderer renderer,
int rowIndex, int vColIndex) {
Component c = super.prepareRenderer(renderer, rowIndex, vColIndex);
if (c instanceof JComponent) {
JComponent jc = (JComponent)c;
jc.setToolTipText((String)getValueAt(rowIndex, vColIndex));
}
return c;
}
};