java swing component cannot be resolved

Question

I took the following code from a tutorial:

import javax.swing.*;
import java.util.Date;

public class SwingGUI {

    public static void main( String[] args )
      {
        JFrame f = new JFrame( "test" );
        f.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        f.setSize( 1500, 900 );
        JLabel l = new JLabel( String.format( "%tT", new Date() ) );
        f.add(l);
        f.setVisible( true );
      }
}

The f.add(l); is highlighted and two errors are shown:

• The method add(Component) in the type Container is not applicable for the arguments (JLabel)

• The type javax.swing.JComponent cannot be resolved. It is indirectly referenced from required .class files

Being relatively new to java, I do not really understand what Eclipse is trying to tell me. What can I do to make it work?

edit: The code runs without the line f.add(l);, so the problem is not that JFrame or JLabel are not found. After fiddeling around a little I got rid of the first error, but the second still remains. The component cannot be resolved, because it is indirectly referenced. What does that mean?

Answer 1

I faced the same issue and found that my project was using the Java 8 libraries. I installed the Java 7 library, added the same to the project properties by referencing the library from the installed C:\Program Files\Java folder and the error was gone.

Looks like, the new Java 8 version may a different way to resolve the swing component.