AnnotationProcessor and dependencies

Question

I'm using gradle / querydsl and JPA 2.1.

I would like to generate the querydsl metadata using APT (QEntities).

To do that I'm using the gradle-apt-plugin and gradle 4.7

In my project I configured the compileJava option using :

compileJava { options.annotationProcessorGeneratedSourcesDirectory = file("$projectDir/src/generated2/java") }

In my dependencies I added

compile 'org.springframework.boot:spring-boot-starter-data-jpa'" annotationProcessor "com.querydsl:querydsl-apt:$querydslVersion:jpa"

The spring starter adds the org.hibernate.javax.persistence:hibernate-jpa-2.1-api:1.0.0.Final jar that contains javax.persistence.Entity class to the compileClasspath.

When launching the compileJava task I got the error : caused by: java.lang.NoClassDefFoundError: javax/persistence/Entity at com.querydsl.apt.jpa.JPAAnnotationProcessor.createConfiguration(JPAAnnotationProcessor.java:37)

Don't understand why the annotation processor cannot load this class.

Answer 1

In case somebody else is searching. This is my full solution (based on your response). The important parts are the net.ltgt.apt* plugins to activate the code generation also in eclipse, and the last three querydsl dependencies.

buildscript {
    ext {
        springBootVersion = '2.0.5.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}


plugins { // activates the automatic code generation
    id 'net.ltgt.apt' version '0.18'
    id 'net.ltgt.apt-eclipse' version '0.18' 
}


apply plugin: 'java'
apply plugin: 'eclipse-wtp'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
apply plugin: 'war'

group = 'com.test'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

configurations {
    providedRuntime
}


dependencies {
    runtimeOnly             'com.h2database:h2'
    implementation          'org.springframework.boot:spring-boot-starter-actuator'
    implementation          'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation          'org.springframework.boot:spring-boot-starter-web'
    providedRuntime         'org.springframework.boot:spring-boot-starter-tomcat'


    testImplementation      'org.springframework.boot:spring-boot-starter-test'
    testImplementation      'org.springframework.boot:spring-boot-starter-webflux'

    // querydsl
    annotationProcessor     'com.querydsl:querydsl-apt:4.1.3:jpa'
    annotationProcessor     'org.springframework.boot:spring-boot-starter-data-jpa' // needed because the query dsl annotation processor doesn't recognize javax.persistence.Entity
    compile                 'com.querydsl:querydsl-jpa:4.1.3'
}