Java ByteBuffer convert to String by CharsetDecoder

import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;
import java.util.Arrays;
public class Main {
  public static void main(String[] argv) throws Exception {
    ByteBuffer bb = ByteBuffer.wrap("demo2s.com".getBytes());

    System.out.println(Arrays.toString(toArray(bb)));
    bb.flip();//from w w w . ja  v  a 2  s  .com
    CharSequence string = getCharSequence(bb, Charset.defaultCharset().newDecoder());
    System.out.println(string);
  }


  public static CharSequence getCharSequence(final ByteBuffer buf, final CharsetDecoder decoder) {
    final ByteBuffer buffer = buf.slice();
    // Find the NUL terminator and limit to that, so the
    // StringBuffer/StringBuilder does not have superfluous NUL chars
    int end = indexOf(buffer, (byte) 0);
    if (end < 0) {
      end = buffer.limit();
    }
    buffer.position(0).limit(end);
    try {
      return decoder.reset().onMalformedInput(CodingErrorAction.REPLACE)
          .onUnmappableCharacter(CodingErrorAction.REPLACE).decode(buffer);
    } catch (CharacterCodingException ex) {
      throw new Error("Illegal character data in native string", ex);
    }
  }

  public static int indexOf(ByteBuffer buf, byte value) {
    if (buf.hasArray()) {
      byte[] array = buf.array();
      int begin = buf.arrayOffset() + buf.position();
      int end = buf.arrayOffset() + buf.limit();
      for (int offset = 0; offset < end && offset > -1; ++offset) {
        if (array[begin + offset] == value) {
          return offset;
        }
      }
    } else {
      int begin = buf.position();
      for (int offset = 0; offset < buf.limit(); ++offset) {
        if (buf.get(begin + offset) == value) {
          return offset;
        }
      }
    }
    return -1;
  }
  
  public static byte[] toArray(final ByteBuffer buffer) {
    byte[] array = new byte[buffer.limit()];
    buffer.get(array);
    return array;
  }
}