macOS java help please

[nownot]

ok heres my code what ive been trying to do is make it where when a textbox is click or tabbed to the text inside will be highlighted and editable. like selectall but i cant work it out, any ideas or help, thanks.

// A program to demonstrate the use of JTextFields's

//Import Statements
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import java.applet.*;
import java.util.Random;
import javax.swing.event.*;
import java.util.Vector;



public class done extends JFrame {
run now = new run();
JTextField field1, field2, field3, field4, field5, field6;
String disp;
JButton pick = new JButton("pick for me");
ButtonPick buttonpick = new ButtonPick();

public done()
{

super("TextField Test Demo");
Container container = getContentPane();
container.setLayout(new GridLayout(10,1));
field1 = new JTextField("Put Choice Here", 15);field2 = new JTextField("Put Choice Here", 15);
field3 = new JTextField("Put Choice Here", 15);field4 = new JTextField("Put Choice Here", 15);
field5 = new JTextField("Put Choice Here", 15);field6 = new JTextField("This is what your doing today", 15);
container.add(field1);container.add(field2);container.add(field3);container.add(field4);container.add(field5);
container.add(pick);
container.add(field6);

pick.addActionListener(buttonpick);
setSize(325, 500);
setVisible(true);

}

private class ButtonPick implements ActionListener{
public void actionPerformed(ActionEvent e){
now.again(field1.getText(),field2.getText(),field3.getText(),field4.getText(),field5.getText());
field6.setText(now.back("String six"));
}
}
public static void main(String args[])
{
done test = new done();
run now = new run();
test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

}



import java.io.*;
import java.util.Random;

public class run {
String[] now = new String[10];
int i = 0;
String here;

public void again(String one, String second, String three, String four, String five){
Random r = new Random();
now[0]=one;now[1]=second;now[2]=three;now[3]=four;now[4]=five;
int z = r.nextInt(5);

if(now[z].equals("Put Choice Here")){
here="you didnt put anything here pls choose again";
}
if(!now[z].equals("Put Choice Here")){
here=now[z];
}


}

public String back(String back){
back = here;
return back;

}


}