java.lang.ClassFormatError: Absent Code attribute

问题:

I have a maven dependency for javaee Bibliothek.

<dependency>
    <groupId>javax</groupId>
    <artifactId>javaee-api</artifactId>
    <version>6.0</version>
    <scope>provided</scope>
</dependency>

I get the error in Eclipse in some classes.

java.lang.ClassFormatError: Absent Code attribute in method that is not native or abstract in class file javax/mail/MessagingException

I added javax.mail dependency.

<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4.5</version>
</dependency>

It did not not work. Any Idea??

回答1:

It doesn't work because classes from javax/javaee-api/provided dependency are specially constructed. They are not usable runtime because implementation of methods is missing.

Simply adding classes from javax.mail/mail/1.4.5 dependency to the classpath does not help, because classes from javax/javaee-api/provided are already there. Having javax.mail/mail/1.4.5 dependecy alone solves your problem, but most likely you also need other classes from javax/javaee-api/provided.

What you can do is to get rid of javax/javaee-api/provided dependency and get these classes for example from the dependencies provided by target application server. You can use for example following:

   <dependency>
        <groupId>org.jboss.spec</groupId>
        <artifactId>jboss-javaee-6.0</artifactId>
        <version>1.0.0.Final</version>
        <type>pom</type>
        <scope>provided</scope>
     </dependency>

Because scope is provided, it does not affect the artifact to be built. That's why you can use this one also with other application servers than JBoss. It is same API as in your original dependency, but it contains normal classes.

回答2:

in my case, only use the library:

<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4</version>
</dependency>

Run with JDK 6 and Tomcat without problems

回答3:

Weird but the following order works for me,

    <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>mail</artifactId>
        <version>1.4</version>
    </dependency>

    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>6.0</version>
        <scope>provided</scope>
    </dependency>

The reverse won't work.

回答4:

If you add them to your pom in this order: javax.mail javaee-web-api it is pretty logical that it will work, because the runtime finds the necessary class first (with the proper implementation) from javax.mail, ignoring any similar class (without implementation) from javaee-web-api.