Java binary compatibility issue: sun.font.FontManager class became interface

Question

I am using the Lobo - Java Web Browser library, and it gives me an exception which after some research I determined could be due to the library having been complied against an older version of Java.

The code is as follows:

import java.io.IOException;
import org.lobobrowser.html.UserAgentContext;
import org.lobobrowser.html.parser.DocumentBuilderImpl;
import org.lobobrowser.html.parser.InputSourceImpl;
import org.lobobrowser.html.test.SimpleUserAgentContext;
import org.xml.sax.SAXException;

public class Cobratest
{
    public static void main(String[] args) throws SAXException, IOException
    {
        UserAgentContext uAgent = new SimpleUserAgentContext();
        DocumentBuilderImpl docBuild = new DocumentBuilderImpl(uAgent);
        docBuild.parse(new InputSourceImpl("http://dic.amdz.com/"));
    }
}

and the stack trace is:

 Exception in thread "main" java.lang.IncompatibleClassChangeError: Found interface sun.font.FontManager, but class was expected
    at org.lobobrowser.util.gui.FontFactory.createFont(FontFactory.java:210)
    at org.lobobrowser.util.gui.FontFactory.createFont_Impl(FontFactory.java:180)
    at org.lobobrowser.util.gui.FontFactory.createFont(FontFactory.java:127)
    at org.lobobrowser.util.gui.FontFactory.getFont(FontFactory.java:98)
    at org.lobobrowser.html.style.StyleSheetRenderState.<clinit>(StyleSheetRenderState.java:43)
    at org.lobobrowser.html.domimpl.NodeImpl.<clinit>(NodeImpl.java:39)
    at org.lobobrowser.html.parser.DocumentBuilderImpl.createDocument(DocumentBuilderImpl.java:143)
    at org.lobobrowser.html.parser.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:97)

when I examined org.lobobrowser.util.gui.FontFactory.createFont I found out there is an interface called FontManager which changed from the previous version of Java. In this FontFactory class, they used a class of this interface which is no longer available. How can I fix this problem?

the interface FontManager:

package sun.font;

import java.awt.Font;
import java.awt.FontFormatException;
import java.io.File;

public interface FontManager {

    public static final int NO_FALLBACK = 0;
    public static final int PHYSICAL_FALLBACK = 1;
    public static final int LOGICAL_FALLBACK = 2;

    public boolean registerFont(Font font);

    public void deRegisterBadFont(Font2D font2d);

    public Font2D findFont2D(String string, int i, int i1);

    public Font2D createFont2D(File file, int i, boolean bln, CreatedFontTracker cft) throws FontFormatException;

    public boolean usingPerAppContextComposites();

    public Font2DHandle getNewComposite(String string, int i, Font2DHandle fdh);

    public void preferLocaleFonts();

    public void preferProportionalFonts();
}

and the class used in the library which is not available:

   return FontManager.getCompositeFontUIResource(new Font(name, style, size));

Answer 1

I think 'sun.font.FontManager'was removed with Java7, so if you must use it (I'd recommend against it and look for another package instead) you could try running it with java6.

Answer 2

The LoboBrowser project has been superseded by LoboEvolution, but there's a patch that's mentioned for the obsolete LoboBrowser implementation.

Update FontFactory.java to import a public method and revise the createFont method as follows:

import static javax.swing.text.StyleContext.*;

private Font createFont(String name, int style, int size) {
  return getDefaultStyleContext().getFont(name, style, size);
}