On 28/03/2025 13:05, Engebretson, John wrote:
Hi all! This message is to discuss the proposal for a public class
that is faster/cheaper than ByteArrayOutputStream. Details are on the
ticket [1] so I will only summarize here:
- ByteArrayOutputStream is slower than the provided alternative, and
wastes memory bandwidth and allocation.
- The new alternative cannot replace ByteArrayOutputStream because
BAOS exposes two implementation-specific fields.
- The problem is broadly present, and different solutions exist in
Spring, Tomcat, multiple applications inside my company, and
undoubtedly elsewhere.
- There are places within the JDK that will benefit from the improved
performance.
There are many possible directions and APIs that could be explored here,
lots of fun.
The JBS issue seems to all about BAOS performance, esp. due to it
maintaining a contiguous array and needing to resize. Rather than
introduce a subclass into the API then maybe you instead explore adding
a static factory that returns a BAOS with a different implementation.
For a long time we've been mulling over adding a factory method to get a
BAOS that isn't thread safe (the undocumented synchronization dates from
JDK 1.0 and too risky to change after 30 years of usage). It would also
be feasible to have BOAS use a different implementation when used
directly vs. when subclassed although that wouldn't be pretty.
-Alan
