Our Android project uses Java 8 Does Kotlin or compiling our kotlinlang #android

I think if you target Java 11 on the Kotlin side, it will be able to optimize the byte code slightly more, but I can’t find a source on this anymore. Just vague memories.

Nick

02/01/2023, 6:33 PM

If you want to make use of optimizations available in newer versions of Java, you can explicitly specify the target Java version from 9 to 19.

I see this from here, I wonder what optimizations there are?

Landry Norris

02/01/2023, 6:34 PM

I’d imagine there’s more things that are guaranteed in a Java 11 runtime than a Java 8 runtime, as there’s more time for the runtime maintainers to implement changes.

The latest new bytecode instruction to my knowledge is invokedynamic in Java 7.

ephemient

02/01/2023, 6:44 PM

if your minSdk is not >= 26, d8 will desugar invokedynamic back to lambda classes anyway

the biggest benefit IMO is being able to freely use newer libraries. you can't use an

inline fun

from a library that was built with Java 11 bytecode in a project that targets Java 8

desugaring supports a growing number of Java 11 APIs as well, https://developer.android.com/studio/write/java11-minimal-support-table https://developer.android.com/studio/write/java11-default-support-table https://developer.android.com/studio/write/java11-nio-support-table

Nick

02/01/2023, 7:08 PM

If we upgrade to Java 11, do we still need to desugar to get the

java.time

package?

sorry not really a kotlin question

ephemient

02/01/2023, 7:09 PM

for Android, yes. there's a difference between the bytecode target and the APIs available at runtime

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but note that the desugared

java.time

is missing various localization features as compared the real implementation, due to limitations of older SDKs

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Nick

02/01/2023, 7:43 PM

Is there anything bad that could happen when we upgrade to java 11 from 8?

Landry Norris

02/01/2023, 7:44 PM

Are you using any of the java.security functions? Those tend to be the main thing I see break when upgrading.

Nick

02/01/2023, 7:46 PM

Copy code

val hasher = MessageDigest.getInstance("SHA-256")
            val hash = hasher.digest(data.toByteArray(Charsets.UTF_8))
            return Base64.encodeToString(hash, Base64.NO_WRAP)

just that

Landry Norris

02/01/2023, 7:46 PM

SHA-256 should be fine.

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ephemient

02/01/2023, 7:56 PM

on Android, those would break on SDK changes and not Java target changes anyway (https://developer.android.com/guide/topics/security/cryptography#deprecated-functionality)

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