Would running android’s R8 over a compose desktop ...
# compose-desktopu
ursus
10/15/2025, 2:38 AMWould running android’s R8 over a compose desktop jar help anything perf wise?
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jw
10/15/2025, 3:28 AMFor sure
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ursus
10/15/2025, 3:19 PMhmm byt that token, would R8 help ktor/spring boot as well? Say with startup?
j
jw
10/15/2025, 8:55 PMYep. Fewer classes to load means less I/O. Fewer methods means less bytecode to verify. Overall that's lower memory pressure and improved performance.
jw
10/15/2025, 8:55 PMUsing ProGuard is a good start, though
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ursus
10/15/2025, 8:59 PMCan I run R8 over jar? Or why do you mention proguard?
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jw
10/15/2025, 9:14 PMYes, R8 has both a Dalvik bytecode backend and a Java bytecode backend
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ursus
10/15/2025, 9:17 PMUhm are you maybe aware of a gradle plugin or do I just try to grab the R8 binary from internet and use it directly?
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jw
10/15/2025, 9:30 PMI use it directly, but you kinda need to know what you're doing
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ursus
10/15/2025, 9:31 PMcompose desktop app, nothing special, usual gradle build, I'm not necessarily unsatisfied with startup speed but if there's something not too difficult I could apply as part of release binary then I want it
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jw
10/15/2025, 9:32 PMSurely someone has come up with a Gradle plugin for this
jw
10/15/2025, 9:32 PMThe feature request for first-party support is https://youtrack.jetbrains.com/issue/CMP-5121
jw
10/15/2025, 9:33 PMI have some manual usage here https://github.com/JakeWharton/dependency-tree-diff/blob/2ce6b2d38c21da0a66ac59afeec23cd75d47c3b7/build.gradle#L71-L93
and here https://github.com/JakeWharton/mosaic/blob/1bc49b953ec64b4489a483486f94c228cefff733/mosaic-tty/build.gradle#L170-L203
if you're interested in looking at those
jw
10/15/2025, 9:33 PMNo Compose UI for JVM examples, though
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ursus
10/15/2025, 9:33 PMBtw what about the latest java? Isn't there an effort to minimaze memory usage, which should improve java ui apps by default significantly?
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jw
10/15/2025, 9:34 PMJava 25 uses compact object headers by default now. Previously it was an experimental, opt-in feature.
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ursus
10/15/2025, 9:34 PMI have some manual usage here..oh neat thank you!
j
jw
10/15/2025, 9:34 PMThat will reduce memory pressure which also means more code can fit into the code cache so it should also improve performance.
jw
10/15/2025, 9:35 PMIn general I would expect every new Java release to be faster than the last, so using the latest is always a good idea.
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ursus
10/15/2025, 9:36 PMYea, I'm currently lamenting if I should bundle jre with the compose app or not, due to the size it adds; but I guess this should be worth it
Btw kotlin will work with it just fine? Doesn't kotlinc emit something older that would not take advantage of the compact object headers etc?
j
jw
10/15/2025, 9:41 PMIt's a VM feature. Has nothing to do with the bytecode
jw
10/15/2025, 9:42 PMBut yes, Kotlin hasn't used anything new in bytecode since like Java 11
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ursus
10/15/2025, 9:42 PMI see
are they waiting for valhalla to drop? 😄
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Colton Idle
10/16/2025, 1:27 PMfwiw. i did some size comparisons with progurad here: https://dev.to/coltonidle/compose-for-desktop-app-size-comparison-3d8h
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ursus
10/16/2025, 1:29 PMNice
btw that is proguard however right? Isnt R8 supposed to be more aggressive -> more savings?
c
Colton Idle
10/16/2025, 1:32 PMcorrect. proguard is built in so i just used that.
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