When decoding an uninterlaced 8-bit PNG image, the PNGImageDecoder is basically copying one byte at a time.
This PR uses System.arraycopy instead, and it shows approx a 10% improvement. This graph shows the time it takes different decoders to convert a byte array into a BufferedImage as the size of the PNG image increases: <img width="596" height="366" alt="Screenshot 2025-12-27 at 9 14 19 PM" src="https://github.com/user-attachments/assets/73583cb2-eda0-47a8-b818-735a1835f1e8"; /> (This originally came to my attention when looking at an image in Java 1.8. There the ImageConsumer model took approx 400% longer than ImageIO. I was happy to see in recent JDKs that gap narrowed significantly, but there was still a noticeable 10% discrepancy.) I haven't tried submitting a performance enhancement PR before; I'm not sure if this issue meets this group's threshold for being worth addressing. And if it does: I'm not sure how to structure a unit test for it. ------------- Commit messages: - 8374377: Use System.arraycopy when possible Changes: https://git.openjdk.org/jdk/pull/29004/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29004&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8374377 Stats: 291 lines in 2 files changed: 287 ins; 0 del; 4 mod Patch: https://git.openjdk.org/jdk/pull/29004.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/29004/head:pull/29004 PR: https://git.openjdk.org/jdk/pull/29004
