dest = growBuffer(dest, destIndex, sizeNeeded);
      }
      s.getChars(lastEscape, slen, dest, destIndex);
      destIndex = sizeNeeded;
    }
    return new String(dest, 0, destIndex);
  }

  /**
   * Helper method to grow the character buffer as needed, this only happens once in a while so it's
   * ok if it's in a method call. If the index passed in is 0 then no copying will be done.
   */

    if (charsSkipped > 0) {
      int endIndex = destIndex + charsSkipped;
      if (dest.length < endIndex) {
        dest = growBuffer(dest, destIndex, endIndex);
      }
      s.getChars(unescapedChunkStart, end, dest, destIndex);
      destIndex = endIndex;
    }
    return new String(dest, 0, destIndex);
  }

  /**

    if (charsSkipped > 0) {
      int endIndex = destIndex + charsSkipped;
      if (dest.length < endIndex) {
        dest = growBuffer(dest, destIndex, endIndex);
      }
      s.getChars(unescapedChunkStart, end, dest, destIndex);
      destIndex = endIndex;
    }
    return new String(dest, 0, destIndex);
  }

  /**

   * @since 11.0
   */
  public static String getFileExtension(String fullName) {
    checkNotNull(fullName);
    String fileName = new File(fullName).getName();
    int dotIndex = fileName.lastIndexOf('.');
    return (dotIndex == -1) ? "" : fileName.substring(dotIndex + 1);
  }

  /**
   * Returns the file name without its <a
   * href="http://en.wikipedia.org/wiki/Filename_extension">file extension</a> or path. This is

        byte[] dest = new byte[5];

        // Expect IndexOutOfBoundsException from System.arraycopy
        assertThrows(IndexOutOfBoundsException.class, () -> {
            encodable.encode(dest, 3); // destIndex=3, len=3, dest.length=5. 3+3 > 5
        }, "Should throw IndexOutOfBoundsException if destination offset + length exceeds destination array bounds");
    }

    @Test
    void testEncodeNullSourceArray() {

   * @since 11.0
   */
  public static String getFileExtension(String fullName) {
    checkNotNull(fullName);
    String fileName = new File(fullName).getName();
    int dotIndex = fileName.lastIndexOf('.');
    return (dotIndex == -1) ? "" : fileName.substring(dotIndex + 1);
  }

  /**
   * Returns the file name without its <a
   * href="http://en.wikipedia.org/wiki/Filename_extension">file extension</a> or path. This is