How to register created fonts in Java 5?

Question

Java 6 provides the registerFont(Font) method in GraphicsEnvironment to register fonts created using Font's createFont(int, InputStream) method. However, I need my application to work using Java 5.
I looked in the Java 6 source code hoping to find the solution. In Java 6, GraphicsEnvironment's registerFont(Font) method calls a static method also entitled registerFont(Font) on the platform class sun.font.FontManager. Based on the code in sun.font.FontManager, I created a class for use in my application which only contains the variables and methods necessary for the registerFont(Font) method.
There is only one problem: the registerFont(Font) method in sun.font.FontManager relies on the use of a native+ method to derive a Font2D object from the created font. The method is: public static native Font2D getFont2D(Font). Although my program compiles, I get the following error message at runtime:
Exception in thread "Thread-3" java.lang.UnsatisfiedLinkError: getFont2D
     at MyFontManager.getFont2D(Native Method)
     at MyFontManager.registerFont(MyFontManager.java:105)
     at java.lang.Thread.run(Unknown Source)
How do I derive a Font2D object from a Font object?
OR
Using Java 5, how do I register a created font such that I can reference that font via its family name, as in the following lines of code (the Java 6 solution is crossed out)?
this.simpleAttributeSet = new SimpleAttributeSet();
try {
InputStream inputStream = getClass().getResource("fonts/FONT.TTF").openStream();
Font font = Font.createFont(Font.TRUETYPE_FONT, inputStream).deriveFont(Font.PLAIN, 25);
inputStream.close();
GraphicsEnvironment.getLocalGraphicsEnvironment().registerFont(font);
MyFontManager.registerFont(font);
StyleConstants.setFontFamily(this.simpleAttributeSet, font.getFamily());
} catch (Exception exception) {
System.err.println(exception);
}

Answer 1

Sure.
My strategy was to create a class for use in my application which would only contain all the variables and methods necessary to execute the registerFont(Font) method in the Java 6 version of sun.font.FontManager. The registerFont(Font) method calls two static, native methods: isCreatedFont and getFont2D. Originally, I made the mistake of including these methods in the class I created. The solution: call these methods on sun.font.FontManager.
The Java 5 version of sun.font.FontManager fortunately supports getFont2D, but does not support isCreatedFont. However, it is not necessary for my program to determine whether or not the font is a created font. Therefore, I replaced all instances of calls to isCreatedFont with the value true.
NOTE: The solution works, but my font ended up looking worse than it did using Java 6 and I'm interested in learning why.