code: public void append(final char[] data) {
          if (data == null) {
              return;
          }
          provideCapacity(length + data.length);
          System.arraycopy(data, 0, c, length, data.length);
          length += data.length;
      }
docs: Appends <code>data</code> to the end of this CharBuffer.
  This method involves copying the new data once!
  @param data the char[] to append or null