Cannot find a spring-aspects-4 dependency

Question

I want to upgrade my project to spring 4, however, I get a missing dependency for aspectweaver-1.8.0.M1.jar. When I take a look at the dependency hierarchy, I see that this file is needed by spring-aspects-4.0.0, which has the following in its own pom.xml

<dependency>
  <groupId>org.aspectj</groupId>
  <artifactId>aspectjweaver</artifactId>
  <version>1.8.0.M1</version>
  <scope>compile</scope>
</dependency>

After checking maven repository, I wasn't able to find this artifact since the latest stable version of aspectweaver is 1.7.4.

Now I can't understand two things:

1. Since the scope of this dependency is compile why does my application need it ? I don't want to compile the spring-aspects.jar !!

2. Why is spring-aspects-4.0.0.jar (which is stable) using a non-stable version of a component ? Wouldn't that make spring-aspects-4.0.0 also non-stable ?

Thanks

Answer 1

According to a reported issue at springsource, aspectjweaver is "basically identical to AspectJ 1.7" except that it has early support for Java 8.

As I don't need Java 8 support, I basically added a compile dependency to the latest release version of aspectweaver:

<dependency>
  <groupId>org.aspectj</groupId>
  <artifactId>aspectjweaver</artifactId>
  <version>1.7.4</version>
</dependency>

This ensures that the 1.7.4 is used instead of the milestone release, and is an acceptable workaround for me, for the time being.

Answer 2

To resolve the aspectjweaver dependency, add this repository:

<repository>
    <id>spring-milestones</id>
    <url>http://repo.spring.io/milestone</url>
    <snapshots>
        <enabled>true</enabled>
    </snapshots>
</repository>

This will give you access to version 1.8.0.M1 of aspectjrt, aspectjweaver and aspectjtools.

However, version 1.6 of the aspectj-maven-plugin does not support Java 8.

Yet spring-aspects-4.0.0 has a dependency on aspectjweaver 1.8.0.M1 for Java 8 support.

If you're using Spring 3.2.6 and Java 7, this aspectj-maven-plugin config works:

        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>aspectj-maven-plugin</artifactId>
            <version>1.6</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
                <complianceLevel>1.7</complianceLevel>
                <aspectLibraries>
                    <aspectLibrary>
                        <groupId>org.springframework</groupId>
                        <artifactId>spring-aspects</artifactId>
                    </aspectLibrary>
                </aspectLibraries>
                <showWeaveInfo>true</showWeaveInfo>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>test-compile</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

You might be able to insert an exclusion on aspectjweaver 1.8.0.M1 within the spring-aspects 4.0.0 dependency. And that might allow you to use Spring 4 with Java 7 and all of the 1.7.4 aspectj* dependencies.

In an effort to apply compile-time weaving (CTW) in a Spring 4/Java 8 project, I came across the following posts:

1. Maven, Scala, Spring, AspectJ

2. https://weblogs.java.net/blog/fabriziogiudici/archive/2011/07/19/making-lombok-aspectj-and-maven-co-exist

And here is my solution: https://github.com/javawerks/homeschool/blob/master/pom.xml

It works! Note that this solution uses version 1.8.0.M1 of the 3 aspectj* amigos, which can be found here: http://repo.spring.io/milestone/org/aspectj/

Warning: If your local maven repository does not yet have the maven-antrun-plugin dependencies, you will get " can't find * dependency in maven central " errors. To resolve this issue, copy the dependencies to your main dependencies element; mvn clean compile; remove copied dependencies; and maven-antrun-plugin should find the aspectj* dependencies. Then execute 'mvn clean install' and verify the ajc logging.

Finally,in Intellij you will see a ' cannot resolve symbol ' error for this iajc attribute:

aspectPath="${org.springframework:spring-aspects:jar}"

No worries, it works as expected. It's a maven-antrun-plugin naming convention.

Someday, the aspectj-maven-plugin will be updated to support Java 8, and then we can return to normalcy. That said, the showWeaveInfo="true" logging is much nicer.

Hope this helps. Like so many before me, it took a lot of beer to figure this one out.;)