static  void copy(Reader r,
    Writer w) throws IOException 
{
        char[] buffer = new char [ 1024 * 16 ];
        for ( ; ; )
        {
            int n = r.read( buffer, 0, buffer.length );
            if (n <  0)
                break;
            w.write( buffer, 0, n );
        }
}

 public static  void main(String[] args) throws Exception 
{
        if (args.length != 3)
            throw new IllegalArgumentException( "Wrong number of arguments" );
        args[ 0 ] = args[ 0 ].replace( '/', File.separatorChar );
        File buildFile = new File( args[ 0 ] );
        StringBuffer sb = readFile( buildFile );
        String tokenStr = "< property name=\"" + args[ 1 ] + "\" value=\"";
        int i = sb.indexOf( tokenStr );
        if (i <  0)
            throw new IllegalArgumentException( "Can't find token: " + tokenStr );
        int j = i + tokenStr.length();
        while ( sb.charAt( j ) != '"' )
            j++;
        sb.replace( i + tokenStr.length(), j, args[ 2 ] );
        writeFile( buildFile, sb );
}

 static StringBuffer readFile(File f) throws IOException 
{
        InputStream in = new FileInputStream( f );
        Reader r = new InputStreamReader( in );
        StringWriter w = new StringWriter();
        copy( r, w );
        w.close();
        r.close();
        in.close();
        return w.getBuffer();
}

 static  void writeFile(File f,
    StringBuffer chars) throws IOException 
{
        OutputStream out = new FileOutputStream( f );
        Writer w = new OutputStreamWriter( out );
        Reader r = new StringReader( chars.toString() );
        copy( r, w );
        r.close();
        w.close();
        out.close();
}