SpringBoot gradle multimodule project Unresolved reference error - spring-boot

Question

I'm trying to create a multimodule springboot application on gradle, but I get an Unresolved reference error message during build. Gradle config for individual modules is below.
Unresolved reference error on import org.example.finalmultimodule.data.repositories.IPersonRepository during build:
Error:
Directory tree:
BuildTools > Gradle:
Main build.gradle:
plugins {
id("org.springframework.boot") version "2.3.3.RELEASE"
id("io.spring.dependency-management") version "1.0.10.RELEASE"
kotlin("plugin.spring") version "1.4.10"
kotlin("jvm") version "1.4.10"
}
group = "org.example"
version = "1.0-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_11
repositories {
mavenCentral()
}
// Projekty
project(":data") {
apply(plugin = "org.springframework.boot")
apply(plugin = "io.spring.dependency-management")
}
project(":business") {
apply(plugin = "org.springframework.boot")
apply(plugin = "io.spring.dependency-management")
}
project(":api") {
apply(plugin = "org.springframework.boot")
apply(plugin = "io.spring.dependency-management")
}
dependencies {
// Moduly
implementation(project(":core"))
implementation(project(":data"))
implementation(project(":business"))
implementation(project(":api"))
implementation(kotlin("stdlib"))
}
allprojects {
tasks.withType<Test> {
useJUnitPlatform()
}
tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
kotlinOptions {
freeCompilerArgs = listOf("-Xjsr305=strict")
jvmTarget = "11"
}
}
}
Core build.gradle:
plugins {
kotlin("jvm")
}
group = "org.example"
version = "1.0-SNAPSHOT"
repositories {
mavenCentral()
}
dependencies {
// Anotace pro #JsonProperty
implementation("com.fasterxml.jackson.core:jackson-annotations:2.11.2")
implementation(kotlin("stdlib"))
}
Data build.gradle:
plugins {
kotlin("jvm")
}
group = "org.example"
version = "1.0-SNAPSHOT"
repositories {
mavenCentral()
}
dependencies {
// Moduly
implementation(project(":core"))
// Anotace #Component etc...
implementation("org.springframework:spring-context")
// Corutines
implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactor")
// Databaze
implementation("org.springframework.boot:spring-boot-starter-data-r2dbc")
implementation("io.r2dbc:r2dbc-mssql")
implementation(kotlin("stdlib"))
}
Business build.gradle:
plugins {
kotlin("jvm")
}
group = "org.example"
version = "1.0-SNAPSHOT"
repositories {
mavenCentral()
}
dependencies {
implementation(project(":core"))
implementation(project(":data"))
// Kediatr variace na Mediatr
implementation("com.trendyol:kediatr-spring-starter:1.0.14")
implementation(kotlin("stdlib"))
}
Api (springboot) build.gradle:
plugins {
kotlin("jvm")
kotlin("plugin.spring")
}
group = "org.example"
version = "0.0.1-SNAPSHOT"
repositories {
mavenCentral()
}
dependencies {
// Moduly
implementation(project(":core"))
implementation(project(":business"))
// Kediatr variace na Mediatr
implementation("com.trendyol:kediatr-spring-starter:1.0.14")
implementation("org.springframework.boot:spring-boot-starter-rsocket")
implementation("org.springframework.boot:spring-boot-starter-validation")
implementation("org.springframework.boot:spring-boot-starter-webflux")
implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
implementation("io.projectreactor.kotlin:reactor-kotlin-extensions")
implementation("org.jetbrains.kotlin:kotlin-reflect")
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactor")
testImplementation("org.springframework.boot:spring-boot-starter-test") {
exclude(group = "org.junit.vintage", module = "junit-vintage-engine")
}
testImplementation("io.projectreactor:reactor-test")
}

Answer 1

I had a very similar situation where my classes from other modules would not be resolved even though everything looked fine in IntelliJ.
I managed to solve it by explicitly adding
#ComponentScan(basePackages = ["my.package"])
to my spring boot application.
Also, set library projects up like this:
tasks.findByName("bootJar")?.apply {
enabled = false
}
tasks.findByName("jar")?.apply {
enabled = true
}