Question

I’m tinkering with JTables and Vectors for the first time in Java, and I’ve hit an interesting snag. My code compiles correctly, but when I go to run it, I get the following exception:

Exception in thread “main” java.lang.ClassCastException:
java.lang.String cannot be cast to java.util.Vector

I don’t see anywhere where I’m casting, so I’m a bit confused.

Vector<String> columnNames = new Vector<String>();
columnNames.add("Tasks");

Vector<String> testing = new Vector<String>();
testing.add("one");
testing.add("two");
testing.add("three");

table = new JTable(testing, columnNames); // Line where the error occurrs.
scrollingArea = new JScrollPane(table);

My goal is to have a table of JPanels, but I have the same type of error when I try to use a Vector of < taskPanel > Here’s the class that extends JPanel:

class taskPanel extends JPanel
{
    JLabel repeat, command, timeout, useGD;

    public taskPanel()
    {
        repeat = new JLabel("Repeat:");
        command = new JLabel("Command:");
        timeout = new JLabel("Timeout:");
        useGD = new JLabel("Update Google Docs:");

        add(repeat);
        add(command);
        add(timeout);
        add(useGD);
    }
}

Answer 1

You need to use a Vector of Vectors here:

Vector<Vector> rowData = new Vector<Vector>();
rowData.addElement(testing);

JTable table = new JTable(rowData, columnNames); 

For a multi-column Vector table model, see this example.