Getting an error “cannot find symbol” while trying to compile a Kotlin-Java mixed project with Gradle

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1

I’m working on a Java-Kotlin mixed project (not using android). When I try to compile project, I get “cannot find symbol” error wherever I refer to Kotlin class from Java class. I followed instructions in the Kotlin documention and also tried solutions in other questions, but it doesn’t work.

I’ve put all Java files in src/main/java, and all Kotlin files in src/main/kotlin.

Below is build.gradle I’m using.

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
        classpath "com.github.jengelman.gradle.plugins:shadow:$shadowVersion"
    }
}

plugins {
    id 'java'
}

if (!project.getPlugins().hasPlugin('org.jetbrains.kotlin.jvm')) {
    apply plugin: 'org.jetbrains.kotlin.jvm'
}

if (!project.getPlugins().hasPlugin('com.github.johnrengelman.shadow')) {
    apply plugin: 'com.github.johnrengelman.shadow'
}

def properties = new Properties()
new File(project.projectDir, '../../gradle.properties').withInputStream() { properties.load(it) }

group = properties.getProperty('group')
version = properties.getProperty('version')
sourceCompatibility = properties.getProperty('sourceCompatibility')

compileJava.options.encoding = 'UTF-8'

sourceSets {
    main.kotlin.srcDirs += 'src/main/kotlin'
    main.java.srcDirs += 'src/main/java'
}

tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
    kotlinOptions {
        freeCompilerArgs = ['-Xjvm-default=compatibility']
        jvmTarget = '1.8'
    }
}

jar {
    finalizedBy shadowJar
}

repositories {
    jcenter()
    mavenCentral()
}

dependencies {
    compile project(':Compatibility')
    compile 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:' + properties.getProperty('kotlinVersion')
    compile 'com.google.guava:guava:' + properties.getProperty('guavaVersion')
    compile 'com.google.code.gson:gson:' + properties.getProperty('gsonVersion')
    compileOnly 'org.jetbrains:annotations:' + properties.getProperty('annotationsVersion')
}

gradle.properties :

group=foo.bar
version=1.0.0
sourceCompatibility=1.8
kotlinVersion=1.4.10
guavaVersion=29.0-jre
gsonVersion=2.8.6
annotationsVersion=20.0.0

How can I solve this problem?

1 Like
2

Failed to reproduce with a dummy project following your build config. Can you please share some sample project to reproduce?

3

I’m concerned too, and I’m able to reproduce it on Kotlin 1.4.x (worked fine on 1.3.x) : here’s a POC.

https://youtrack.jetbrains.com/issue/KT-42264

The problem is triggered when calling a Kotlin method returning an inline classes from Java:

inline class Baz(val value: Double)

interface Foo {
   fun get(value: Int): Baz
}

// Bar.java
class Bar {

    private final Foo foo;

    private Bar(@NonNull Foo foo) {
        this.foo = foo;
    }

    private double baz(int value) {
        return foo.get(value); // error: cannot find symbol
    }
}

POC.zip (56.8 KB)

1 Like