This code throws an exception:

import java.nio.*;
import java.nio.charset.*;

class bug
{
  public static void main(String[] args) throws Exception
  {
    byte[] data = new byte[] { (byte)0, (byte)129 };
    int offset = 0;
    int count = 2;
    CharsetDecoder csd = Charset.forName("Windows-1252").newDecoder();
    csd.onUnmappableCharacter(CodingErrorAction.REPLACE);
    CharBuffer out = CharBuffer.allocate(count * (int)csd.maxCharsPerByte());
    csd.decode(ByteBuffer.wrap(data, offset, count), out, true);
    csd.flush(out);
    System.out.println(out.flip().toString());
  }
}