How can I create a rollover effect in a JTable?

You must implement your own renderer and for the returned renderer by the getTableCellRendererComponent(...) method should have some mouse listeners (for entering/exiting) attached to him in which you'll change the colors. Something like this (it works for editable checkbox cells):

 import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;

public class RolloverTableCells extends JFrame {
  private SmartTable table;
  private SmartTableModel model;

  public RolloverTableCells() {
    init();
  }

  private void init() {
    getContentPane().setLayout(new BorderLayout());
    setSize(400, 300);
    setLocation(300, 100);
    table = new SmartTable();
    getContentPane().add(new JScrollPane(table), BorderLayout.CENTER);
    setVisible(true);
  }

  class SmartTable extends JTable {

    public SmartTable() {
      model = new SmartTableModel();
      setModel(model);
      createColumns();
      setForeground(Color.red);
      setBackground(new Color(255, 239, 185));
      setGridColor(Color.orange);
      setSelectionMode(ListSelectionModel.SINGLE_SELECTION);


      setRowHeight(35);
      setSelectedRow(0);
      setSelectedCol(0);
    }

    protected void createColumns() {
      for(int i = 0; i<model.getColumnCount(); i++) {
        TableColumn column = getColumn(model.getColumnName(i));
        column.setCellRenderer(new GenericRenderer());
        column.setCellEditor(new GenericEditor());
      }
    }

    public void setSelectedRow(int row) {
      if(row == -1)
        return;
      else {
        setRowSelectionInterval(row, row);
      }
    }

    public void setSelectedCol(int col) {
      if(col == -1)
        return;
      else {
        setColumnSelectionInterval(col, col);
      }
    }
  }

  class SmartTableModel extends AbstractTableModel {
    protected ColumnDescriptor cols[] =  {
      new ColumnDescriptor("Field1", 40, JLabel.LEFT),
      new ColumnDescriptor("Field2", 50, JLabel.LEFT),
      new ColumnDescriptor("Field3", 100, JLabel.LEFT),
    };
    protected Vector dObjects;

    public SmartTableModel() {
      dObjects = new Vector();
      initModelData();
    }

    public void initModelData() {
      Object[] row = new Object[3];
      row[0] = "string"; row[1] = "string"; row[2] = "string";
      dObjects.addElement(row);

      row = new Object[3];
      row[0] = "string"; row[1] = "string"; row[2] = new JButton("button");
      dObjects.addElement(row);

      row = new Object[3];
      row[0] = "string"; row[1] = new JButton("button"); row[2] = "string";
      dObjects.addElement(row);

      row = new Object[3];
      row[0] = "string"; row[1] = new JButton("button"); row[2] = new JCheckBox("checkbox");
      dObjects.addElement(row);

      row = new Object[3];
      row[0] = new JButton("button");row[1] = new JCheckBox("checkbox");row[2] = "string";
      dObjects.addElement(row);

      row = new Object[3];
      row[0] = new JButton("button");row[1] = new JCheckBox("checkbox");row[2] = new JButton("button");
      dObjects.addElement(row);

      row = new Object[3];
      String[] items = {"Item 1", "Item 2", "Item 3"};
      row[0] = new JComboBox(items);row[1] = new JComboBox(items);row[2] = new JComboBox(items);
      dObjects.addElement(row);
      updateObjects();
    }

    protected void updateObjects() { fireTableDataChanged(); }
    public int getColumnCount() {      return(cols.length); }
    public int getRowCount() { return(dObjects.size());      }
    public String getColumnName(int c) { return(cols[c].name); }
    public boolean isCellEditable(int row, int col) {
      return((getObjectAt(row, col) instanceof String)?false:true);
    }

    public Object getObjectAt(int row, int col)  {
      return(((Object[]) dObjects.elementAt(row))[col]);
    }

    public Object getValueAt(int row, int col) {
      if(getRowCount() <= 0)
        return "";
      if(row<0||row>=getRowCount())
        return "";
      Object cellData = ((Object[]) dObjects.elementAt(row))[col];
      return(cellData);
    }
  }

  class ColumnDescriptor {
    public String name;
    public int width;
    public int alignment;

    public ColumnDescriptor(String n, int w, int a) {
      name = n;
      width = w;
      alignment = a;
    }
  }

  class GenericRenderer extends DefaultTableCellRenderer {
    public Component getTableCellRendererComponent(JTable table, Object value,
    boolean isSelected, boolean hasFocus, int row, int col) {
      Object o = model.getObjectAt(row, col);
      if(o instanceof JButton || o instanceof JCheckBox || o instanceof JComboBox) {
        if(o instanceof JCheckBox)
          ((Component) o).setBackground(table.getBackground());
        return((Component) o);
      }
      Component c = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, col);
      return(c);
    }
  }

  class GenericEditor extends DefaultCellEditor {
    JTable tbl;
    private int lastRow = 0;
    private int lastCol = 0;
    private Component editor;

    public GenericEditor() {
      super(new JCheckBox());
    }
    public Component getTableCellEditorComponent(JTable t, Object v, boolean sel, int r, int c) {
      tbl = t;
      lastRow = r;
      lastCol = c;
      Object o = model.getObjectAt(r, c);
      if(o instanceof JButton || o instanceof JCheckBox || o instanceof JComboBox)
        editor = (Component) o;
      else
        editor = new JTextField(v.toString());
      editor.addMouseListener(new MouseAdapter() {
        public void mouseEntered(MouseEvent me) {
          editor.setBackground(Color.red);
        }
        public void mouseExited(MouseEvent me) {
          editor.setBackground(Color.white);
        }
      });
      return(editor);
    }

    public Object getCellEditorValue() {
      return(model.getObjectAt(lastRow, lastCol));
    }
    public boolean isCellEditable(java.util.EventObject ev) {      return(true); }
    public boolean shouldSelectCell(java.util.EventObject ev) {      return(false); }
    public boolean stopCellEditing() {
      tbl.editingStopped(new ChangeEvent(this));
      return(true);
    }
    public void cancelCellEditing() {}
    public void addCellEditorListener(CellEditorListener cel) {}
    public void removeCellEditorListener(CellEditorListener cel) {}
  }

  public static void main(String[] args) {
    RolloverTableCells t = new RolloverTableCells();
  }
}

Instead of using the DefaultTableCellRenderer, define you own that returns an instance of a rollover button as the rendering component.
Let me know if you need a hand.

Ovi:
I tried your code, however, the components you placed in the cells did not react to the MouseAdapter until it had the focus.  I also tried to add the MouseAdapter within the cell renderer, but it didn't work.

objects:
I have created my own cell renderers that extended the DefaultTableCellRenderer.  I also know that the TableCellRenderer interface has only the one method getTableCellEditorComponent(). However, I could use some help in creating an instance of a rollover button.  Unless you know a better way, I feel that the same thing will happen as with Ovi's code (that is, the button will not change its background color until it has the focus).

Thanks for your assistance.

"Something like this (it works for editable checkbox cells):"

Although I would have preferred not to use a JButton for the cells that I want to display the rollover effect, it is useful when you are displaying data in a JTable that need to respond to a mouse click.  Thanks for your help.