`StyleManager.calculateCheckSum()` uses a raw InputStream as the input to a `DigestInputStream` and reads one byte at a time. This is slower in performance and should be changed, either to use `BufferedInputStream` or read byte buffer of 4096 from the stream or use both.
I have tried three approaches and tested with modena.css which is ~134 KB in size. Following are the approaches and time in milliseconds taken by the method StyleManager.calculateCheckSum(), collected from 25 readings, 1. Use BufferedInputStream and read one byte at a time [commit#1](https://github.com/openjdk/jfx/commit/6cd7d44d0ce1084c6cdb06a698c7aca127a615ef) : - Maximum: 53 ms, Minimum: 27 ms, Average: 39 ms 2. Use BufferedInputStream and read buffer of 4096 at a time [commit#1+2](https://github.com/openjdk/jfx/pull/518/files/6e0c621ea62691d5402b2bca5951d1012a5b1b91) - Maximum: 17 ms, Minimum: 14 ms, Average: 15.58 ms 3. Use raw InputStream(current implementation) and read buffer of 4096 at a time [commit#1+2+3](https://github.com/openjdk/jfx/pull/518/files/215e1a183cfb902247f0d48685f7a901cb5fb003), which also similar to `NativeLibLoader.calculateCheckSum()` and looks faster than previous two. - Maximum: 16 ms, Minimum: 13 ms, Average: 14.25 ms The time taken by `StyleManager.calculateCheckSum()` with current implementation is, - Maximum: 61 ms, Minimum: 38 ms, Average: 50.58 ms Both approaches 2 & 3 show good improvement. I would prefer approach#3 as it is similar to `NativeLibLoader.calculateCheckSum()`. However we can choose approach#2 also. If we choose approach#3 then bug summary should be changed accordingly. ------------- Commit messages: - only buffer[4096], similar to NativeLibLoader.calculateCheckSum() - BufferedInputStream + buffer[4096] - use BufferedInputStream Changes: https://git.openjdk.java.net/jfx/pull/518/files Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=518&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8239138 Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod Patch: https://git.openjdk.java.net/jfx/pull/518.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/518/head:pull/518 PR: https://git.openjdk.java.net/jfx/pull/518
