AspectJ in Gradle - Intellij Idea

Question

For a whole day i've been trying to use AspectJ - adding dependencies, installing plugins, creating .aj files or marking with @Aspect annotation, but nothing seems to work on gradle. Please help me to understand my problem.

My GreetingAspect.aj file

package org.example;

public aspect GreetingAspect {

    pointcut greeting() : execution(* Main.printName(..));

    before() : greeting() {
        System.out.print("Hello ");
    }
}

The code should print "Hello (name)" before every instance of .printName(), so i can see that "poincut" and "before" is working

1. My build.gradle

plugins {
    id 'java'
    id "io.freefair.aspectj" version "8.3"
}

group = 'org.example'
version = '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

dependencies {

    testImplementation platform('org.junit:junit-bom:5.9.1')
    testImplementation 'org.junit.jupiter:junit-jupiter'

    runtimeOnly 'org.aspectj:aspectjweaver:1.9.7'
    runtimeOnly 'org.aspectj:aspectjrt:1.9.7'
    implementation 'org.aspectj:aspectjtools:1.9.7'

}

test {
    useJUnitPlatform()
}

3. Main

package org.example;

public class Main {

    public static void main(String[] args) {
        printName("Max");
        printName("John");
        printName("Martin");
    }

    public static void printName(String name) {
        System.out.println(name);
    }
}

I tried to: Install AspectJ plugin from market, that added support for .aj, but they seem to do nothing at all, install AspectJ plugins from https://plugins.gradle.org/, Installing .jar directly in lib, Changing version from 1.9.10 to 1.9.7, instead of .aj using .java classes but with @Aspect annotation.

Answer 1

Maybe you have both source files in src/main/java or only the aspect in src/main/aspectj, but in the default configuration, Freefair expects all source files to reside in src/main/aspectj:

Then, the project works flawlessly.

---

[Optional] You can, however, also streamline your Gradle build config a little bit and also update AspectJ to a more recent version, because 1.9.7 only supports Java 16, but 1.9.20 supports up to Java 20.

plugins {
  id 'java'
  id "io.freefair.aspectj" version "8.3"
}

group = 'org.example'
version = '1.0-SNAPSHOT'

repositories {
  mavenLocal()
  mavenCentral()
}

dependencies {
  testImplementation platform('org.junit:junit-bom:5.9.1')
  testImplementation 'org.junit.jupiter:junit-jupiter'
  implementation 'org.aspectj:aspectjrt:1.9.20'
}

test {
  useJUnitPlatform()
}

---

Update 2023-10-10: Freefair 8.4 now defaults to src/main/java, i.e. it works as expected with a standard directory layout, just like with AspectJ Maven.