Como mostrar um html dentro Jframe

package exemplos2;

import javax.swing.*;
import java.awt.*;

public class DisplayHtml{

  public DisplayHtml(String urlString){
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container con = frame.getContentPane();

    JEditorPane jep = new JEditorPane();
    JScrollPane jsp = new JScrollPane(jep);
    con.add(jsp);

    jep.setContentType("text/html");
    try{
      jep.setPage(urlString);
    }
    catch (Exception e){
      e.printStackTrace();
    }

    frame.setBounds(50, 50, 600, 800);
    frame.setVisible(true);
  }

  public static void main(String[] args){
    String ustr = "file://C:\\mytest.html";

    if (args.length > 0){ // local file URL should begin with file://
      ustr = args[0];     // ex.  file:///root/mytest.html
    }                     // ex.  file://C:\mytest.html
    new DisplayHtml(ustr);
  }
}

package pasta1;

import javax.swing.*;
import java.awt.*;
import java.io.IOException;

public class DisplayHtml{

	public DisplayHtml() throws IOException{
		JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		Container con = frame.getContentPane();

		JEditorPane jep = new JEditorPane("file:/C:/mytest.html");
		JScrollPane jsp = new JScrollPane(jep);
		con.add(jsp);

		frame.setBounds(50, 50, 600, 500);
		frame.setVisible(true);
	}

	public static void main(String[] args) throws IOException{
		DisplayHtml exibeHtml=new DisplayHtml();
	}
}

import javax.swing.*;
import java.awt.*;
import java.io.IOException;
import java.text.CharacterIterator;
import java.text.StringCharacterIterator;

public class ConceitoHtml{

	public ConceitoHtml() throws IOException{
		JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		Container con = frame.getContentPane();

		String URL = ("file:///"+System.getProperty("user.dir") + "/src/Arv/image/paginaloca.html");

		String novo=URLCaracteresInvalidos(URL);

		JEditorPane jep = new JEditorPane(novo);
		JScrollPane jsp = new JScrollPane(jep);
		con.add(jsp);

		frame.setBounds(50, 50, 600, 500);
		frame.setVisible(true);
	}
	public static String URLCaracteresInvalidos(String URL){  

		final StringBuilder resultado = new StringBuilder();  
		final StringCharacterIterator iterator = new StringCharacterIterator(URL);  
		char character =  iterator.current();  
		while (character != CharacterIterator.DONE ) {  
			if (character == '\\') {  
				resultado.append("/");  
			} else if (character == ' ') {  
				resultado.append("%20");  
			} else {   
				resultado.append(character);  
			}  
			character = iterator.next();  
		}  
		return resultado.toString();  
	}  
	public static void main(String[] args) throws IOException{
		ConceitoHtml exibeHtml=new ConceitoHtml();
	}
}