question abpout characters.

hi! all, have a look on this code
class Charvalue
{
public static void main(String[] args)
{
for (int i = 0x0004;i <=0xFFFE;i++ )
{
System.out.println(i );
System.out.println((char)i);
}
}
}
In the output i get some of the character but most of the output is consist of question mark (?). Can anybody tell me why it's so?

That's normal. Most of the characters will not be defined in the font or codepage that you are using. E.g. You won't get Japanese characters if you haven't installed Japanese fonts.
There is also a file that is part of the JRE that tells the java run time what characters are available.
Look for jre/lib/font.*