Maven + AspectJ - all steps to configure it

Question

I have a problem with applying aspects to my maven project. Probably I am missing something, so I've made a list of steps. Could you please check if it is correct?

Let say in projectA is an aspect class and in projectB classes, which should be changed by aspects.

• Create maven project ProjectA with AspectJ class
• add Aspectj plugin and dependency
• Add ProjectA as a dependency to projectB pom.xml
• Add to projectB pom.xml plugin

<plugin>     <groupId>org.codehaus.mojo</groupId>     <artifactId>aspectj-maven-plugin</artifactId>     <version>1.4</version>     <executions>         <execution>             <goals>                 <goal>compile</goal>                 <goal>test-compile</goal>             </goals>         </execution>     </executions>     <configuration>         <source>${maven.compiler.source}</source>         <target>${maven.compiler.target}</target>         <aspectLibraries>             <aspectLibrary>                 <groupId>ProjectA</groupId>                 <artifactId>ProjectA</artifactId>             </aspectLibrary>         </aspectLibraries>     </configuration> </plugin> 

• Add aspectj dependency

After all these steps my problem is, that during compilation I get:

[WARNING] advice defined in AspectE has not been applied [Xlint:adviceDidNotMatch] 

And then when I run my program:

Exception in thread "FeatureExcutionThread" java.lang.NoClassDefFoundError: AspectE 

Answer 1

I traced some of your older questions to try to find out what you actually are trying to do. I have come up with the following structure and code and for me it works well.

 $ tree . . ├── pom.xml ├── ProjectA |   ├── pom.xml |   └── src |       └── main |           └── aspect |               └── com |                   └── stackoverflow |                       └── aspects |                           ├── AspectL.java |                           └── Trace.aj └── ProjectB     ├── pom.xml     └── src         └── main             └── java                 └── com                     └── stackoverflow                         └── App.java 

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">     <modelVersion>4.0.0</modelVersion>      <groupId>org.stackoverflow</groupId>     <artifactId>Q12423965</artifactId>     <packaging>pom</packaging>     <version>1.0-SNAPSHOT</version>      <name>${project.artifactId}-${project.version}</name>      <properties>         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>         <maven.compiler.source>1.6</maven.compiler.source>         <maven.compiler.target>1.6</maven.compiler.target>     </properties>      <modules>         <module>ProjectA</module>         <module>ProjectB</module>     </modules>      <dependencyManagement>         <dependencies>             <dependency>                 <groupId>org.stackoverflow</groupId>                 <artifactId>Q12423965-ProjectA</artifactId>                 <version>${project.version}</version>             </dependency>         </dependencies>     </dependencyManagement>      <build>         <pluginManagement>             <plugins>                 <plugin>                     <groupId>org.codehaus.mojo</groupId>                     <artifactId>aspectj-maven-plugin</artifactId>                     <version>1.4</version>                     <executions>                         <execution>                             <goals>                                 <goal>compile</goal>                                 <goal>test-compile</goal>                             </goals>                         </execution>                     </executions>                     <configuration>                         <source>${maven.compiler.source}</source>                         <target>${maven.compiler.target}</target>                     </configuration>                 </plugin>                 <plugin>                     <groupId>org.apache.maven.plugins</groupId>                     <artifactId>maven-compiler-plugin</artifactId>                     <version>2.5.1</version>                     <configuration>                         <source>${maven.compiler.source}</source>                         <target>${maven.compiler.target}</target>                     </configuration>                 </plugin>             </plugins>         </pluginManagement>     </build> </project> 

ProjectA/pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">     <modelVersion>4.0.0</modelVersion>      <parent>         <groupId>org.stackoverflow</groupId>         <artifactId>Q12423965</artifactId>         <version>1.0-SNAPSHOT</version>     </parent>      <artifactId>Q12423965-ProjectA</artifactId>      <name>${project.artifactId}-${project.version}</name>      <dependencies>         <dependency>             <groupId>org.aspectj</groupId>             <artifactId>aspectjrt</artifactId>             <version>1.6.11</version>         </dependency>     </dependencies>      <build>         <plugins>             <plugin>                 <groupId>org.codehaus.mojo</groupId>                 <artifactId>aspectj-maven-plugin</artifactId>             </plugin>         </plugins>     </build> </project> 

I have created two differenct aspects. One that uses @AspectJ annotations and another one that is defined as a classic AspectJ aspect.

AspectL.java

package com.stackoverflow.aspects;  import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.After; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut;  /**  * @author maba, 2012-09-18  */ @Aspect public class AspectL {      @Pointcut("execution(* main(..))")     public void defineEntryPoint() {     }      @Before("defineEntryPoint()")     public void aaa(JoinPoint joinPoint) {         System.out.println("aspect before");     }      @After("defineEntryPoint()")     public void bbb(JoinPoint joinPoint) {         System.out.println("aspect after");     } } 

Trace.aj

package com.stackoverflow.aspects;  public aspect Trace {     pointcut publicMethodExecuted(): execution(public !static * *(..));      after(): publicMethodExecuted() {         System.out.printf("Enters on method: %s. \n", thisJoinPoint.getSignature());          Object[] arguments = thisJoinPoint.getArgs();         for (int i =0; i < arguments.length; i++){             Object argument = arguments[i];             if (argument != null){                 System.out.printf("With argument of type %s and value %s. \n", argument.getClass().toString(), argument);             }         }         System.out.printf("Exits method: %s. \n", thisJoinPoint.getSignature());     } } 

Those two files are part of the ProjectA module and are part of a jar.

Now we want to use these aspects and weave them into the code of ProjectB.

ProjectB/pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">     <modelVersion>4.0.0</modelVersion>      <parent>         <groupId>org.stackoverflow</groupId>         <artifactId>Q12423965</artifactId>         <version>1.0-SNAPSHOT</version>     </parent>      <artifactId>Q12423965-ProjectB</artifactId>      <name>${project.artifactId}-${project.version}</name>      <dependencies>         <dependency>             <groupId>org.aspectj</groupId>             <artifactId>aspectjrt</artifactId>             <version>1.6.11</version>         </dependency>         <dependency>             <groupId>org.stackoverflow</groupId>             <artifactId>Q12423965-ProjectA</artifactId>         </dependency>     </dependencies>      <build>         <plugins>             <plugin>                 <groupId>org.codehaus.mojo</groupId>                 <artifactId>aspectj-maven-plugin</artifactId>                 <configuration>                     <aspectLibraries>                         <aspectLibrary>                             <groupId>org.stackoverflow</groupId>                             <artifactId>Q12423965-ProjectA</artifactId>                         </aspectLibrary>                     </aspectLibraries>                 </configuration>             </plugin>             <plugin>                 <groupId>org.codehaus.mojo</groupId>                 <artifactId>exec-maven-plugin</artifactId>                 <version>1.2.1</version>                 <executions>                     <execution>                         <goals>                             <goal>java</goal>                         </goals>                     </execution>                 </executions>                 <configuration>                     <mainClass>com.stackoverflow.App</mainClass>                 </configuration>             </plugin>         </plugins>     </build> </project> 

App.java

package com.stackoverflow;  /**  * @author maba, 2012-09-17  */ public class App {      public void hello(String name) {     }      public static void main(String[] args) {         App app = new App();         app.hello("world");     } } 

I build everything from top pom:

mvn clean install 

And then go into the ProjectB directory and run the app:

mvn exec:java 

The result is:

aspect before Enters on method: void com.stackoverflow.App.hello(String).  With argument of type class java.lang.String and value world.  Exits method: void com.stackoverflow.App.hello(String).  aspect after 

So to conclude both aspects are working and the maven setup also works.

Answer 2

This worked for me, a had to add the lookup for external dependencies (see weaveDependencies) in order to perform weaving to them, you should include this in ProjectA pom file:

<dependencies>   <dependency>     <groupId>com.ProjectB</groupId>     <artifactId>ProjectB</artifactId>   </dependency>   <dependency>     <groupId>org.aspectj</groupId>     <artifactId>aspectjrt</artifactId>     <version>1.6.5</version>   </dependency> </dependencies>  <build>   <plugins>     <plugin>       <groupId>org.codehaus.mojo</groupId>       <artifactId>aspectj-maven-plugin</artifactId>       <version>1.2</version>       <executions>         <execution>           <goals>             <goal>compile</goal><!-- to weave all your main classes -->             <goal>test-compile</goal><!-- to weave all your test classes -->           </goals>         </execution>       </executions>       <configuration>         <weaveDependencies>            <weaveDependency>             <groupId>com.ProjectB</groupId>             <artifactId>ProjectB</artifactId>           </weaveDependency>         </weaveDependencies>         <showWeaveInfo>true</showWeaveInfo>          <source>${maven.compiler.source}</source>         <target>${maven.compiler.target}</target>       </configuration>     </plugin>   </plugins> </build> 

Hope it helps...