Как мне удалить недопустимые символы XML из потока в J2ME? org.xml.sax.SAXParseException: недопустимый символ

public class StripReader extends Reader
{
    private Reader in;
    public StripReader(Reader in)
    {
    this.in = in;
    }

    public boolean markSupported()
    {
    return false;
    }

    public void mark(int readLimit)
    {
    throw new UnsupportedOperationException("Mark not supported");
    }

    public void reset()
    {
    throw new UnsupportedOperationException("Reset not supported");
    }

    public int read() throws IOException
    {
    int next;
    do
    {
        next = in.read();
    } while(!(next == -1 || Character.isValidCodePoint(next)));

    return next; 
    }

    public void close() throws IOException
    {
    in.close();
    }

    public int read(char[] cbuf, int off, int len) throws IOException
    {
    int i, next = 0;
    for(i = 0; i < len; i++)
    {
        next = read();
        if(next == -1)
        break;
        cbuf[off + i] = (char)next;
    }
    if(i == 0 && next == -1)
        return -1;
    else
        return i;
    }

    public int read(char[] cbuf) throws IOException
    {
    return read(cbuf, 0, cbuf.length);
    }
}