import javax.swing.JFrame;
import javax.swing.JTextField;
import java.awt.Color;

public class FrameTester {
    public static void main (String [] args) {
        Color initialGreen = new Color(50,200,50);   
        Color paleGreen = initialGreen.brighter();
        JFrame frame = new JFrame();
        frame.setSize(400,400);
        JTextField text = new JTextField("Hello, Alex!");
        text.setBackground(paleGreen);
        frame.add(text);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}