Can't import java package on custom plugin

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1

I’ve created Java or Kotlin Library on Android Studio.
I selected Kotlin and Kotlin DSL.

here is my build.gradle.kts
build.gradle.kts

plugins {
    java
    `kotlin-dsl`
    `java-library`
    id("java")
}

java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(21)
    }
}

sourceSets {
    main {
        java.srcDir("src/main/java")
        kotlin.srcDir("src/main/kotlin")
    }
}

Then to create custom plugin make a Kotlin file, but cannot resolve java.util.Optional

import org.gradle.jvm.toolchain.JavaToolchainRequest
import org.gradle.jvm.toolchain.JavaToolchainResolver
import java.util.Optional

abstract class ResolverTest: JavaToolchainResolver {
    override fun resolve(request: JavaToolchainRequest): Optional {
        TODO("Not yet implemented")
    }
}

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image704×281 29.5 KB

What else I’ve missing?
How can I resolve java.util.Optional?
Any suggestions?
Thank you.

2

Do you get the same error if you try to build through Gradle?

I suspect that simply your JDK in the IDE is not set properly.

Btw. the whole “sourceSets” block is useless, you just configure again what already is the default.

3

Thank you for your answer.
I hardly understand Do you get the same error if you try to build through Gradle?
That means I would run the build task?

I suspect that simply your JDK in the IDE is not set properly.

How can I set property it? Does toolchain doesn’t help it?

Btw. the whole “sourceSets” block is useless, you just configure again what already is the default.

I will remove that sourceSets, thank you.

4

That means I would run the build task?

For example, yes.
Or actually as you just want to see whether it compiles compileKotlin would also be enough.

How can I set property it?

Check your IDE project settings.

Does toolchain doesn’t help it?

Probably depends on your IDE and its version.
Latest IJ versions should usually support I think.
But there could also be bugs in that support as it is relatively new.