Lower overhead String encoding/decoding

Ulf Zibis Ulf.Zibis at CoSoCo.de
Mon Sep 22 12:43:02 UTC 2014

Compare with https://bugs.openjdk.java.net/browse/JDK-6695386
Maybe that would help a little.


Am 22.09.2014 um 13:25 schrieb Richard Warburton:
> Hi all,
> A long-standing issue with Strings in Java is the ease and performance of
> creating a String from a ByteBuffer. People who are using nio to bring in
> data off the network will be receiving that data in the form of bytebuffers
> and converting it to some form of String. For example restful systems
> receiving XML or Json messages.
> The current workaround is to create a byte[] from the ByteBuffer - a
> copying action for any direct bytebuffer - and then pass that to the
> String. I'd like to propose that we add an additional constructor to the
> String class that takes a ByteBuffer as an argument, and directly create
> the char[] value inside the String from the ByteBuffer.
> Similarly if you have a String that you want to encode onto the wire then
> you need to call String.getBytes(), then write your byte[] into a
> ByteBuffer or send it over the network. This ends up allocating a byte[] to
> do the copy and also trimming the byte[] back down again, usually
> allocating another byte[]. To address this problem I've added a couple of
> getBytes() overloads that take byte[] and ByteBuffer arguments and write
> directly to those buffers.
> I've put together a patch that implements this to demonstrate the overall
> direction.
> http://cr.openjdk.java.net/~rwarburton/string-patch-webrev-5/
> I'm happy to take any feedback on direction or the patch itself or the
> overall idea/approach. I think there are a number of similar API situations
> in other places as well, for example StringBuffer/StringBuilder instances
> which could have similar appends directly from ByteBuffer instances instead
> of byte[] instances.
> I'll also be at Javaone next week, so if you want to talk about this, just
> let me know.
> regards,
>    Richard Warburton
>    http://insightfullogic.com
>    @RichardWarburto <http://twitter.com/richardwarburto>
> PS: I appreciate that since I'm adding a method to the public API which
> consequently requires standardisation but I think that this could get
> incorporated into the Java 9 umbrella JSR.

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