Gradle, Kotlin, Multi Module Project: Getting build errors while compiling this project - spring-boot

Question

I am getting the following error on running gradle build command on root folder.
E:\Code\mdh>gradle build
> Task :multidemo:compileKotlin FAILED
e: E:\Code\mdh\multidemo\src\main\kotlin\com\simbalarry\multidemo\SampleController.kt: (3, 23): Unresolved reference: somelib
e: E:\Code\mdh\multidemo\src\main\kotlin\com\simbalarry\multidemo\SampleController.kt: (18, 12): Unresolved reference: Tester
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':multidemo:compileKotlin'.
> Compilation error. See log for more details
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 5s
4 actionable tasks: 1 executed, 3 up-to-date
Below is my project structure and multidemo project is using some functionalities of somelib. Also, I have deliberetly kept somelib as spring boot project as I will be adding more spring boot related functionalities later.
Root Project
|
|---settings.gradle
|---somelib
| |
| |---build.gradle
| |---settings.gradle
| |---src/main/kotlin/somepackage/Tester.kt
| |---src/main/kotlin/somepackage/SomeLibApplication.kt
|
|---multidemo
| |---build.gradle
| |---settings.gradle
| |---src/main/kotlin/somepackage/SampleController.kt
| |---src/main/kotlin/somepackage/MultidemoApplication.kt
Below are the contents of every file
Root/settings.gradle
include ':somelib', ':multidemo'
somelib/build.gradle
plugins {
id 'org.springframework.boot' version '2.1.3.RELEASE'
id 'org.jetbrains.kotlin.jvm' version '1.3.21'
id 'org.jetbrains.kotlin.plugin.spring' version '1.3.21'
}
apply plugin: 'io.spring.dependency-management'
group = 'com.simbalarry'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'com.fasterxml.jackson.module:jackson-module-kotlin'
implementation 'org.jetbrains.kotlin:kotlin-reflect'
implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
compileKotlin {
kotlinOptions {
freeCompilerArgs = ['-Xjsr305=strict']
jvmTarget = '1.8'
}
}
compileTestKotlin {
kotlinOptions {
freeCompilerArgs = ['-Xjsr305=strict']
jvmTarget = '1.8'
}
}
somelib/settings.gradle
pluginManagement {
repositories {
gradlePluginPortal()
}
}
rootProject.name = 'somelib'
somelib/src/main/kotlin/somepackage/Tester.kt
package com.simbalarry.somelib
/*
* Created on : 17-03-2019
* Author : Nayan Kurude
*/
object Tester {
fun getOutputText(): String {
return "Sample Text"
}
}
somelib/src/main/kotlin/somepackage/SomelibApplication.kt
package com.simbalarry.somelib
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
#SpringBootApplication
class SomelibApplication
fun main(args: Array<String>) {
runApplication<SomelibApplication>(*args)
}
multidemo/build.gradle
plugins {
id 'org.springframework.boot' version '2.1.3.RELEASE'
id 'org.jetbrains.kotlin.jvm' version '1.3.21'
id 'org.jetbrains.kotlin.plugin.spring' version '1.3.21'
}
apply plugin: 'io.spring.dependency-management'
group = 'com.simbalarry'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
mavenCentral()
mavenLocal()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'com.fasterxml.jackson.module:jackson-module-kotlin'
implementation 'org.jetbrains.kotlin:kotlin-reflect'
implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8'
compile project(':somelib')
testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
compileKotlin {
kotlinOptions {
freeCompilerArgs = ['-Xjsr305=strict']
jvmTarget = '1.8'
}
}
compileTestKotlin {
kotlinOptions {
freeCompilerArgs = ['-Xjsr305=strict']
jvmTarget = '1.8'
}
}
multidemo/settings.gradle
pluginManagement {
repositories {
gradlePluginPortal()
}
}
rootProject.name = 'multidemo'
multidemo/src/main/kotlin/somepackage/MultiDemoApplication.kt
package com.simbalarry.multidemo
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
#SpringBootApplication
class MultidemoApplication
fun main(args: Array<String>) {
runApplication<MultidemoApplication>(*args)
}
multidemo/src/main/kotlin/somepackage/SampleController.kt
package com.simbalarry.multidemo
import com.simbalarry.somelib.Tester
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RestController
/*
* Created on : 17-03-2019
* Author : Nayan Kurude
*/
#RestController
class SampleController {
#RequestMapping("/hello")
fun hello(): String {
return Tester.getOutputText()
}
}
Could anyone please tell me where am i doing something wrong.

Answer 1

As I said in comments: somelib is supposed to be a library. So it shouldn't apply the spring boot plugin, whose role is to create a Spring Boot application.
Your build.gradle file for somelib should look like this:
plugins {
id 'java-library' // 1
id 'org.springframework.boot' version '2.1.3.RELEASE' apply false // 2
id 'io.spring.dependency-management' version '1.0.6.RELEASE' //3
id 'org.jetbrains.kotlin.jvm' version '1.3.21'
id 'org.jetbrains.kotlin.plugin.spring' version '1.3.21'
}
group = 'com.simbalarry'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
mavenCentral()
}
dependencyManagement { // 4
imports {
mavenBom org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES
}
}
ext['kotlin.version'] = '1.3.21' // 5
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'com.fasterxml.jackson.module:jackson-module-kotlin'
implementation 'org.jetbrains.kotlin:kotlin-reflect'
implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
compileKotlin {
kotlinOptions {
freeCompilerArgs = ['-Xjsr305=strict']
jvmTarget = '1.8'
}
}
compileTestKotlin {
kotlinOptions {
freeCompilerArgs = ['-Xjsr305=strict']
jvmTarget = '1.8'
}
}
Some explanations (see the comments in the code):
Applies the java library gradle plugin, since that's what you want to create: a library that can be used in the other project
Adds the Spring Boot plugin to the classpath of the build without applying it, in order to be able to use its BOM later. See https://docs.spring.io/spring-boot/docs/2.1.3.RELEASE/gradle-plugin/reference/html/#managing-dependencies-using-in-isolation
Applies the spring dependency management plugin to be able to specify dependencies without version, by using the version numbers specified in the spring boot BOM
Configure the dependency management plugin to use the spring boot BOM
Override the kotlin version used in the BOM (1.2.71) by the one you want to use. See https://docs.spring.io/dependency-management-plugin/docs/current-SNAPSHOT/reference/html/#dependency-management-configuration-bom-import-override-property