Is it on the application's class path?  If so, you can..

  URL theFontURL = this.getClass().getResource("theFontFile");

..then..

  InputStream stream = theFontURL.openStream();

HTH

here is my SCCE.  It baffles me. It seems to find and construct the
Font from the jar just fine, but when I use it, I just see Dialog. I
tried in with three different TTF files, same result.

package com.mindprod.example;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontFormatException;
import java.awt.Frame;
import java.awt.Label;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.io.InputStream;
/**
* How to include a custom font with your application.<br>
* Demonstrate use of java.awt.Font.createFont<br>
* Accessing an uninstalled Font bundled in a jar or on the
classpath.<br>
* Note this technique is illegal if you don't have licensing
permission from
* the font designer.
*
* @author Roedy Green
*/
public class TestCreateFont {

   /**
    * Debugging harness for a Frame
    *
    * @param args
    *        command line arguments are ignored.
    * @throws FontFormatException
    *         if font is not a valid TrueType font
    * @throws IOException
    *         if there is some problem reading the font file.
    */
   public static void main ( String args[] ) throws
FontFormatException,
       IOException
       {
       final Frame frame = new Frame();
       // Uninstalled font is a resource on classpath or in jar named
       // "com/mindprod/example/verdana.ttf"

       InputStream fontStream = TestCreateFont.class
           .getResourceAsStream( "verdana.ttf" );
       Font onePoint = Font.createFont( Font.TRUETYPE_FONT,
fontStream );
       fontStream.close();
       Font snowFont = onePoint.deriveFont( Font.PLAIN, 18 );
       System.out.println ( snowFont);
       
       Label Label = new Label( "Snow Alert" );
       Label.setBackground( Color.BLACK );
       Label.setForeground( Color.WHITE );
       Label.setFont( snowFont );
     
       frame.add( Label );
       frame.setSize( 100, 100 );
       frame.addWindowListener( new WindowAdapter() {

           /**
            * Handle request to shutdown.
            *
            * @param e
            *        event giving details of closing.
            */
           public void windowClosing ( WindowEvent e )
               {
               System.exit( 0 );
               } // end WindowClosing
       } // end anonymous class
           ); // end addWindowListener line
       frame.validate();
       frame.setVisible( true );
       } // end main
}

This works. The trick is this does not work in AWT, only Swing. see
http://mindprod.com/jgloss/font.html#BUNDLING
and
http://mindprod.com/jgloss/font.html#GOTCHAS

package com.mindprod.example;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontFormatException;
import java.io.IOException;
import java.io.InputStream;

import javax.swing.JFrame;
import javax.swing.JLabel;
/**
* How to include a custom font with your application.<br>
* Demonstrate use of java.awt.Font.createFont<br>
* Accessing an uninstalled Font bundled in a jar or on the
classpath.<br>
* Note this technique is illegal if you don't have licensing
permission from
* the font designer.
* This only works in Swing!
*
* @author Roedy Green
*/
public class TestCreateFont {

   /**
    * Debugging harness for a Frame
    *
    * @param args
    *        command line arguments are ignored.
    * @throws FontFormatException
    *         if font is not a valid TrueType font
    * @throws IOException
    *         if there is some problem reading the font file.
    */
   public static void main ( String args[] ) throws
FontFormatException,
       IOException
       {
       final JFrame frame = new JFrame();

       // Uninstalled font is a resource on classpath or in jar named
       // "com/mindprod/example/IGLOOLAS.TTF"
       // This example font is a decorative font with snowcaps
       // on the capital letters.

       InputStream fontStream = TestCreateFont.class
           .getResourceAsStream( "IGLOOLAS.TTF" );
       Font onePoint = Font.createFont( Font.TRUETYPE_FONT,
fontStream );
       fontStream.close();
       Font snowFont = onePoint.deriveFont( Font.PLAIN, 18 );
       System.out.println( snowFont );

       JLabel label = new JLabel( "SNOW ALERT" );
       label.setBackground( Color.WHITE );
       label.setForeground( Color.BLACK );
       label.setFont( snowFont );

       frame.add( label );
       frame.setSize( 300, 100 );
       frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
       frame.validate();
       frame.setVisible( true );
       } // end main
} // end class