Review/comment needed for the new public java.util.Base64 class

Stephen Colebourne scolebourne at
Thu Oct 11 09:43:20 UTC 2012

The class level javadoc is quite short. It also has hyperlinks in the
first sentence, which means that they are visible in package level
javadoc. Consider having no hyperlinks in the first sentence, and
expanding a little on what base 64 is.

There are lots of other public base 64 implementations to test/check against.  (claims to be fast)

The arrays are defined inconsistently within the code (3 styles).
  private Encoder(byte[] base64, byte[] newline, int linemax)
  byte [] getBytes(ByteBuffer bb)
  private static final byte toBase64[] =
I'd strongly encourage one style be used, and that it is the first of
the three above.


On 10 October 2012 18:54, Xueming Shen <xueming.shen at> wrote:
> A standard/public API for Base64 encoding and decoding has been long
> overdue. JDK8  has a JEP [1] for this particular request.
> Here is the draft proposal to add a public Base64 utility class for JDK8.
> This class basically provides 4 variants of Base64 encoding scheme,
> (1) the default RFC 4648, which uses standard mapping, no line breaks,
> (2) the URL-safe RFE 4648, no line breaks, use "-" and "_" to replace "+"
> and
>     "/" for the mapping
> (3) the default MIME style, as in RFC 2045 (and its earlier versions), which
> uses
>     "standard" base64 mapping, a 76 characters per line limit and uses crlf
> pair
>      \r\n for line break.
> (4) an extend-able MIME base64, with the char-per-line and the line
> separator(s)
>      specified by developer.
> The encoder/decoder now provides encoding and decoding for byte[], String,
> ByteBuffer and a pair of "EncoderInputStream" and "DecoderOutputStrream",
> which we believe/hope should satisfy most of the common use cases.
> Additional
> method(s) can be added if strongly desired.
> We tried couple slightly different styles of design for such this "simple"
> utility
> class [2].  We kinda concluded that the version proposed probably provides
> the best balance among readability, usability and extensibility.
> Please help review and comment on the API and implementation.
> Thanks!
> -Sherman
> [1]
> [2]

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