I can give you the way to access jar resources as URL; to display the retrieved html in your JavaBrowser will be another issue.

check this code:

import java.net.*;
import java.io.*;

public class JarTest {

    URL getJarFileURL(String jarFile, String fileName)
    throws MalformedURLException {
        return new URL("jar:file:" + jarFile + "!/" + fileName);
    }

    void printInputStream(InputStream is) throws IOException {
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        while (br.ready()) {
            System.out.println(br.readLine());
        }
        br.close();
    }

    public void displayInMyBroser(URL url) {
        // MyJavaBrowser mjb = new MyJavaBrowser();
        // mjb.showURL(url);
    }

    public void displayJarFile(String jarFile, String fileName)
    throws MalformedURLException, IOException {
        URL u = getJarFileURL(jarFile, fileName);
        printInputStream(u.openStream());
        // displayInMyBrowser(u);
    }

    public static void main(String[] args) throws Exception {
        String jarFile = "D:/JBuilder4/doc/langspec.jar";
        String fileName = "java/langspec/intro.doc.html";
        new JarTest().displayJarFile(jarFile, fileName);
    }
}