In Java, you can set the column width and row height for a JTable component using the setPreferredWidth method of the TableColumn class and the setRowHeight method of the JTable class.

Here's an example of how to do this:

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

public class TableExample extends JFrame {

    private final JTable table;

    public TableExample() {
        super("Set Column Width and Row Height for JTable");

        // Create a new table model with some data
        DefaultTableModel model = new DefaultTableModel(new Object[][]{
                {"John", "Doe", 30},
                {"Jane", "Doe", 25},
                {"Bob", "Smith", 45},
                {"Sally", "Johnson", 35},
        }, new String[]{"First Name", "Last Name", "Age"});

        // Create a new JTable with the table model
        table = new JTable(model);

        // Set the preferred width of the "First Name" column to 100 pixels
        TableColumn column = table.getColumnModel().getColumn(0);
        column.setPreferredWidth(100);

        // Set the preferred width of the "Last Name" column to 100 pixels
        column = table.getColumnModel().getColumn(1);
        column.setPreferredWidth(100);

        // Set the row height to 30 pixels
        table.setRowHeight(30);

        // Add the table to a scroll pane and the frame
        JScrollPane scrollPane = new JScrollPane(table);
        add(scrollPane);

        // Set the size, location and visibility of the frame
        pack();
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }

    public static void main(String[] args) {
        new TableExample();
    }
}

In this example, we create a JTable component and set its column width and row height using the setPreferredWidth and setRowHeight methods.

To set the preferred width of a column, we first get the TableColumn object for the column using the getColumnModel method of the JTable class. We then call the setPreferredWidth method on the column object and pass in the desired width in pixels.

To set the row height, we simply call the setRowHeight method on the JTable object and pass in the desired height in pixels.

When you run this example, a window will appear with a JTable that has the first and last name columns set to 100 pixels and the row height set to 30 pixels.