AspectJ - parse definitions failed - NullPointerException

问题

Here's MVCE https://github.com/yami12376/AspectJ

Add VM arguments to Run/Debug configuration of Junit test, in my case:

-javaagent:C:\aspectjWeaver\spring-instrument-3.0.4.jar

-javaagent:C:\aspectjWeaver\aspectjweaver-1.6.11.jar
In my case i added this in JAVA build path: \target\classes\META-INF from src/main/resources
Run Junit test

If you delete aop.xml it's still weaving type org.*

but on the other hand aop.xml should not weave it beacuse it has: <include within="com.*"/> Why does it weave something other than com.* ?

Finally i want that MyAspect will be called when running Junit test based on @Around("execution(* *(..))")

As you can see now it is not getting called.

I've made my example based on https://docs.spring.io/spring/docs/current/spring-framework-reference/html/aop.html#aop-aj-ltw-first-example

When running JUnit test i see this error:

http://wklej.org/id/3066582/

 [AppClassLoader@18b4aac2] warning parse definitions failed -- (NullPointerException) null
null
java.lang.NullPointerException
    at org.aspectj.weaver.loadtime.definition.DocumentParser.resolveEntity(DocumentParser.java:177)
    at org.apache.xerces.util.EntityResolverWrapper.resolveEntity(Unknown Source)
    at org.apache.xerces.impl.XMLEntityManager.resolveEntity(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentScannerImpl$DTDDispatcher.dispatch(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
    at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
    at org.aspectj.weaver.loadtime.definition.DocumentParser.saxParsing(DocumentParser.java:158)
    at org.aspectj.weaver.loadtime.definition.DocumentParser.parse(DocumentParser.java:123)
    at org.aspectj.weaver.loadtime.ClassLoaderWeavingAdaptor.parseDefinitions(ClassLoaderWeavingAdaptor.java:272)
    at org.aspectj.weaver.loadtime.DefaultWeavingContext.getDefinitions(DefaultWeavingContext.java:130)
    at org.aspectj.weaver.loadtime.ClassLoaderWeavingAdaptor.initialize(ClassLoaderWeavingAdaptor.java:156)
    at org.aspectj.weaver.loadtime.Aj$ExplicitlyInitializedClassLoaderWeavingAdaptor.initialize(Aj.java:340)
    at org.aspectj.weaver.loadtime.Aj$ExplicitlyInitializedClassLoaderWeavingAdaptor.getWeavingAdaptor(Aj.java:345)
    at org.aspectj.weaver.loadtime.Aj$WeaverContainer.getWeaver(Aj.java:319)
    at org.aspectj.weaver.loadtime.Aj.preProcess(Aj.java:113)
    at org.aspectj.weaver.loadtime.ClassPreProcessorAgentAdapter.transform(ClassPreProcessorAgentAdapter.java:54)
    at sun.instrument.TransformerManager.transform(Unknown Source)
    at sun.instrument.InstrumentationImpl.transform(Unknown Source)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.access$100(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

I want to fix this error

回答1:

Well, you have several strange issues and errors in your project:

Obviously your POJO application does not use Spring. So you can get rid of Spring dependencies and also of spring-instrument.jar on your command line. You also do not need core-context.xml.
Xerces is also not needed as far as I can see.
If you use aspectjweaver.jar as a dependency, aspectjrt.jar is superfluous because the former is a superset and thus contains the latter.
In aop.xml there is a package name typo: Please use com.mkyong in the aspect name, not com.mykong. Otherwise the aspect will never be found.
In your include within tag you should use .. syntax in order to in-/exclude also subpackages.
Your aspect class is a total mess:
- You use nested classes for no apparent reason.
- You use @Around, but JoinPoint instead of ProceedingJoinPoint in the advice signature.
- You use @Around, but never call proceed().

So how about this?

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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.mkyong</groupId>
  <artifactId>NumberGenerator</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>NumberGenerator</name>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>1.8.10</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.0</version>
        <configuration>
          <source>1.7</source>
          <target>1.7</target>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

aop.xml:

<?xml version="1.0" encoding="UTF-8"?>
<aspectj>
  <aspects>
    <aspect name="com.mkyong.MyAspect"/>
  </aspects>
  <weaver options="-verbose -showWeaveInfo">
    <include within="com.mkyong..*"/>
    <exclude within="org.jibx*..*"/>
  </weaver>
</aspectj>

Aspect:

package com.mkyong;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;

@Aspect
public class MyAspect {
  @Around("execution(!static * *(..))")
  public Object dontLogDuplicates(ProceedingJoinPoint thisJoinPoint) throws Throwable {
    System.out.println(thisJoinPoint);
    return thisJoinPoint.proceed();
  }
}

Console log:

I see the following when adding -javaagent:/path/to/aspectjweaver.jar to my JUnit run configuration in IntelliJ IDEA:

[AppClassLoader@18b4aac2] info AspectJ Weaver Version 1.8.10 built on Monday Dec 12, 2016 at 19:07:48 GMT
[AppClassLoader@18b4aac2] info register classloader sun.misc.Launcher$AppClassLoader@18b4aac2
[AppClassLoader@18b4aac2] info using configuration /C:/Users/Alexander/Documents/java-src/yami12376-AspectJ/target/classes/META-INF/aop.xml
[AppClassLoader@18b4aac2] info register aspect com.mkyong.MyAspect
[AppClassLoader@18b4aac2] weaveinfo Join point 'method-execution(void com.mkyong.AppTest.testLengthOfTheUniqueKey())' in Type 'com.mkyong.AppTest' (AppTest.java:9) advised by around advice from 'com.mkyong.MyAspect' (MyAspect.java)
execution(void com.mkyong.AppTest.testLengthOfTheUniqueKey())
[AppClassLoader@18b4aac2] weaveinfo Join point 'method-execution(java.lang.String com.mkyong.App.generateUniqueKey())' in Type 'com.mkyong.App' (App.java:12) advised by around advice from 'com.mkyong.MyAspect' (MyAspect.java)
execution(String com.mkyong.App.generateUniqueKey())

But really, you should fix your POM and make sure that aspect weaving is done from there and not manually. It is really ugly like this.

Update: After all the criticism, let me also say one positive thing: You provided a MCVE, thanks for that. With code fragments, questions and answers we would never have found the many bugs in your files. So it was a smart and prudent decision to create the GitHub project. I could easily spot the problems. :-) If everyone did that, I would save a lot of time here.

来源：https://stackoverflow.com/questions/42906522/aspectj-parse-definitions-failed-nullpointerexception

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