import java.awt.Dimension;
import java.awt.FlowLayout;
import java.util.Arrays;
import java.util.Vector;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;

public class MainFrame extends JFrame {
    DefaultComboBoxModel<String> comboModel;
    JComboBox<String> combo;
    Rank[] rankArray = {
        new Rank(1, "takarító"),
        new Rank(2, "gondnok"),
        new Rank(3, "villanyszerelő"),
    };
    Vector<Rank> rankList = new Vector<>(Arrays.asList(rankArray));

    public MainFrame() {
        setComponent();
        setMainFrame();
    }
    private void setComponent() {
        comboModel = new DefaultComboBoxModel<>();
        combo = new JComboBox<>(comboModel);
        combo.setPreferredSize(new Dimension(100, 32));
        rankList.forEach(rank -> {
            comboModel.addElement(rank.name);
        });    
    }
    private void setMainFrame() {

        this.add(combo);
        this.setLayout(new FlowLayout());
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setSize(400, 300);
        this.setVisible(true);

    }
    
}