Spring Boot + Kotlin AutoProxyRegistrar causes Nullpointer Exception

Question

Hej everyone, I am trying to migrate a small spring boot project from java 8 to kotlin. I ran into an issue where i have the following configuration class

@EnableCaching
@Configuration
open class CacheConfiguration : CachingConfigurer {

    @Bean
    override fun cacheManager(): CacheManager {
        return ConcurrentMapCacheManager()
    }

    @Bean
    override fun cacheResolver(): CacheResolver {
        return SimpleCacheResolver(cacheManager())
    }
    /**
     * Simple Key Generator

     * @return not null
     */
    @Bean
    override fun keyGenerator(): KeyGenerator {
        return SimpleKeyGenerator()
    }

    @Bean
    override fun errorHandler(): CacheErrorHandler {
        return SimpleCacheErrorHandler()
    }

}

This is the actual class. This is literaly the first and only kotlin class in my project. Starting the project now with gradle bootRun results in a Nullpointer exception in

AutoProxyRegistrar.java#L63

 AnnotationAttributes candidate = AnnotationConfigUtils.attributesFor(importingClassMetadata, annoType);
 Object mode = candidate.get("mode"); <-- candidate is null

It tries to retrieve Annotation Attributes, which works well for the 2 Annotations i provided

@EnableCaching
@Configuration

Though it seems that kotlin adds a new annotation called kotlin.Metadata which seemingly can not be processed.

build.gradle

buildscript {
    ext {
        ext.kotlin_version = '1.0.5-2'
        springBootVersion = '1.4.3.RELEASE'
        asciiDoctorVersion = '1.5.2'
        snippetsDir = file('build/generated-snippets')
    }
    repositories {
        jcenter()
        mavenCentral()
        maven { url "https://repo.spring.io/snapshot" }
        maven { url "https://repo.spring.io/milestone" }
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
        classpath("org.asciidoctor:asciidoctor-gradle-plugin:${asciiDoctorVersion}")
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlin_version}")
    }
}

apply plugin: 'java'
apply plugin: 'spring-boot'
apply plugin: 'kotlin'
apply plugin: 'org.asciidoctor.convert'

sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
    jcenter()
    mavenCentral()
    maven { url "https://repo.spring.io/snapshot" }
    maven { url "https://repo.spring.io/milestone" }
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.14'
}

test {
    outputs.dir snippetsDir
    testLogging {
        events "passed", "skipped", "failed", "standardError"
    }
}

task stage {
    dependsOn build
}

asciidoctor {
    attributes 'snippets': snippetsDir
    inputs.dir snippetsDir
    dependsOn test
}

// Force ./gradlew cleanTest
allprojects {
    tasks.matching { task -> task.name == "test" }.all {
        outputs.upToDateWhen { false }
    }
}

dependencies {
    compile(group: 'org.springframework.boot', name: 'spring-boot-starter')
    compile(group: 'org.springframework.boot', name: 'spring-boot-starter-web')
    compile(group: 'org.springframework.boot', name: 'spring-boot-starter-data-jpa')
    compile(group: 'org.springframework.boot', name: 'spring-boot-starter-actuator')
    compile(group: 'org.springframework.boot', name: 'spring-boot-starter-security')
    compile(group: 'org.springframework.security.oauth', name: 'spring-security-oauth2', version: '2.0.10.RELEASE')
    compile(group: 'org.springframework.security', name: 'spring-security-jwt', version: '1.0.4.RELEASE')
    compile(group: 'org.postgresql', name: 'postgresql', version: '9.4.1209.jre7')


    testCompile(group: 'com.jayway.restassured', name: 'rest-assured', version: '2.9.0')
    testCompile(group: 'org.springframework.boot', name: 'spring-boot-starter-test')
}

Reproducible Sample

I have created a small repository to reproduce this issue. https://github.com/spring-projects/spring-framework-issues/pull/145 And This https://jira.spring.io/browse/SPR-15055

Answer 1

This was an actual bug which was fixed here https://jira.spring.io/browse/SPR-15055