Connection con;
	Statement st;
	ResultSet rs;
JComboBox comboBox = new JComboBox();

		try {
			con=DriverManager.getConnection("jdbc:mysql://localhost:3306/transmax?useSSL=false","test","test");
			st=con.createStatement();
			String s = "select * from przewodnik";
			rs = st.executeQuery(s);
			while(rs.next()){
				comboBox.addItem(rs.getString(4)+ " " +  rs.getString(5));
			}
		} finally  {
			st.close();
			rs.close();
			con.close();
		}
		panel.add(comboBox);
	}