Tag Archives: javax.xml

Base64 encoding and decoding performance

by Mikhail Vorontsov

02 Apr 2014 update: added Guava implementation and byte[] < -> byte[] section.

21 Mar 2014 update: major rewrite + added javax.xml.bind.DatatypeConverter class description.

21 Feb 2014 update: added MiGBase64 class description.

25 Dec 2013 update: added Java 8 java.util.Base64 class description.

We will discuss what is Base64 algorithm and what is the performance of several different well-known libraries implementing Base64 encoding/decoding.

Base64 is an algorithm mapping all 256 byte values to 64 printable byte values (printable means that those bytes are printed in US-ASCII encoding). This is done by packing 3 input bytes to 4 output bytes. Base64 is generally used in text-based data exchange protocols when there is still a need to transfer some binary data. The best known example is encoding of e-mail attachments.

JDK Base64 implementations

Surprisingly, there was no Base64 implementation in the core JDK classes before Java 6. Some web forums advise to use two non-public sun.* classes which are present in all Sun/Oracle JDK: sun.misc.BASE64Encoder and sun.misc.BASE64Decoder. The advantage of using them is that you don’t need to ship any other libraries with your application. The disadvantage is that those classes are not supposed to be used from outside JDK classes (and, of course, they can be removed from JDK implementation… in theory, at least).

Sun has added another Base64 implementation in Java 6 (thanks to Thomas Darimont for his remainder!): it was hidden in javax.xml.bind package and was unknown to many developers. javax.xml.bind.DatatypeConverter class has 2 static methods – parseBase64Binary and printBase64Binary, which are used for Base64 encoding and decoding.

Java 8 has finally added a Base64 implementation in the java. namespace – java.util.Base64. This static factory class provides you with the basic/MIME/URL and filename safe encoder and decoder implementations.

Surprisingly (or may be not), all these implementations do not share any logic even in Java 8.

Third party Base64 implementations

I will also mention 4 quite well known Base64 third party implementations.

  • The first one is present in the Apache Commons Codec library and called org.apache.commons.codec.binary.Base64.
  • The next one is present in the Google Guava library and accessible via com.google.common.io.BaseEncoding.base64() static method.
  • Another one was written by Robert Harder and available from his website: http://iharder.net/base64. This is a single class which you will have to add to your project.
  • The last one was written by Mikael Grev nearly 10 years ago. It is available from http://migbase64.sourceforge.net/. This is also a single class you have to add into your project. This implementation claims to be the fastest Base64 implementation, but unfortunately this is not true any longer. Besides, it has a strictest limit on the maximal length of byte[] to decode (see below).

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