Please specify proper '-jvm-target' optionkotlin(INLINE_FROM_HIGHER_PLATFORM)

[laibulle]

Trying to use the plugin with java 11 on OSX.

openjdk 11.0.1 2018-10-16
OpenJDK Runtime Environment 18.9 (build 11.0.1+13)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.1+13, mixed mode)

It is a simple project generate via springr.

I get the following error

Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6. Please specify proper '-jvm-target' optionkotlin(INLINE_FROM_HIGHER_PLATFORM)

You can reproduce using this repo https://github.com/laibulle/spring-kotlin-sample. The code run via

gradle bootRun

Best regards

[fwcd]

This might be related to #20. Java 9+ support is still experimental.

[laibulle]

I switch back to Java 8

java version "1.8.0_192"
Java(TM) SE Runtime Environment (build 1.8.0_192-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.192-b12, mixed mode)

and still have the same message.

[kenpb]

Same problem here, setting the kotlin.compiler.jvmtarget in maven or the jvmTarget in gradle have no effect whatsoever.

java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)

info: kotlinc-jvm 1.3.30-eap-125 (JRE 1.8.0_131-b11)

Any more info we can provide to help out?,
Cheers!

[pcgeek86]

I'm having this same issue. Could you add a VSCode setting to change the version of the jvmTarget attribute? My build.gradle.kts file is set to use the correct jvmTarget, but the Kotlin language server doesn't respect this value.

Here's the relevant portion of my Gradle configuration:

import org.jetbrains.kotlin.gradle.tasks.KotlinCompile

tasks.withType<KotlinCompile> {
    kotlinOptions.suppressWarnings = true
    kotlinOptions.jvmTarget = JavaVersion.VERSION_1_8.toString()
}

The specific error I'm getting is a little different than others, but the root cause is similar.

Calls to static methods in Java interfaces are prohibited in JVM target 1.6. Recompile with '-jvm-target 1.8'kotlin(INTERFACE_STATIC_METHOD_CALL_FROM_JAVA6_TARGET_ERROR)

[mcraveiro]

I've also bumped into this problem. Is there some kind of "brute force" approach to solve this problem? For example, force KLS to always use 1.8. This would be sufficient for my purposes for now since I am using the same Java version on all my projects.

[kuro46]

I have same problem too.
And I created a patch that forcely set jvm-target to 1.8. It works well :)

diff --git a/server/src/main/kotlin/org/javacs/kt/Compiler.kt b/server/src/main/kotlin/org/javacs/kt/Compiler.kt
index 0f223df..e310b90 100644
--- a/server/src/main/kotlin/org/javacs/kt/Compiler.kt
+++ b/server/src/main/kotlin/org/javacs/kt/Compiler.kt
@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.cli.jvm.config.addJvmClasspathRoots
 import org.jetbrains.kotlin.config.CommonConfigurationKeys
 import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.config.JVMConfigurationKeys
+import org.jetbrains.kotlin.config.JvmTarget
 import org.jetbrains.kotlin.container.ComponentProvider
 import org.jetbrains.kotlin.container.get
 import org.jetbrains.kotlin.idea.KotlinLanguage
@@ -49,6 +50,7 @@ class Compiler(classPath: Set<Path>) {
     private val config = CompilerConfiguration().apply {
         put(CommonConfigurationKeys.MODULE_NAME, JvmAbi.DEFAULT_MODULE_NAME)
         put(CLIConfigurationKeys.MESSAGE_COLLECTOR_KEY, LoggingMessageCollector)
+        put(JVMConfigurationKeys.JVM_TARGET, JvmTarget.JVM_1_8)
         addJvmClasspathRoots(classPath.map { it.toFile() })
     }
     val environment: KotlinCoreEnvironment

[mcraveiro]

Genius! thanks @kuro46, applying the patch locally as we speak :-)

[mcraveiro]

Applied, works as advertised! :-) Thanks very much!

[fwcd]

@kuro46 Thank you very much, I will add this as a configuration option to the language server!

[fwcd]

Fixed by #128.