Java: Enum: NoClassDefFoundError

Question

I am having problems using enum in my J2EE application. I use enumeration in case of switching inside my service without bean state.

At runtime, I see the following exception in the switch statement:

Caused by: java.lang.NoClassDefFoundError: com/comp/service/TestServiceImpl$1 

This issue has been widely discussed in one of the threads at https://stackoverflow.com/a/3/2/2/ . But I do not see a solution to solve this problem.

In my case, I am using the JBOSS EAP6.1 server. The JDK version is 1.7. Code built using Maven in the Eclipse IDE. And the application is being deployed as an EAR archive. How to add this additional file of the generated class to the classpath in my EAR archive? Is there any other way to solve this problem?

Update June 29, 2014: I tried to create the application from the command line. Then this extra class file is created. And I can successfully and successfully use the application. Then it seems to be a bug with eclipse. Any idea how to solve it?

pom.xml from the EAR project:

 <?xml version="1.0" encoding="UTF-8"?> <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> <parent> <artifactId>demo-maven</artifactId> <groupId>com.comp.demo</groupId> <version>0.0.1-SNAPSHOT</version> </parent> <artifactId>demo-ear</artifactId> <packaging>ear</packaging> <name>demo - ear</name> <url>www.comp.com</url> <licenses> <license> <name>Apache License, Version 2.0</name> <distribution>repo</distribution> <url>http://www.apache.org/licenses/LICENSE-2.0.html</url> </license> </licenses> <dependencies> <!-- Depend on the ejb module and war so that we can package them --> <dependency> <groupId>com.comp.demo</groupId> <artifactId>demo-web</artifactId> <type>war</type> </dependency> <dependency> <groupId>com.comp.demo</groupId> <artifactId>demo-service</artifactId> <type>ejb</type> </dependency> </dependencies> <build> <finalName>${project.parent.artifactId}</finalName> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-ear-plugin</artifactId> <version>${version.ear.plugin}</version> <configuration> <!-- Tell Maven we are using Java EE 6 --> <version>6</version> <!-- Use Java EE ear libraries as needed. Java EE ear libraries are in easy way to package any libraries needed in the ear, and automatically have any modules (EJB-JARs and WARs) use them --> <defaultLibBundleDir>lib</defaultLibBundleDir> <modules></modules> <fileNameMapping>no-version</fileNameMapping> </configuration> </plugin> <!-- The JBoss AS plugin deploys your ear to a local JBoss EAP container --> <!-- Due to Maven lack of intelligence with EARs we need to configure the jboss-as maven plugin to skip deployment for all modules. We then enable it specifically in the ear module. --> <plugin> <groupId>org.jboss.as.plugins</groupId> <artifactId>jboss-as-maven-plugin</artifactId> <configuration> <skip>false</skip> </configuration> </plugin> </plugins> </build> <profiles> <profile> <!-- When built in OpenShift the 'openshift' profile will be used when invoking mvn. --> <!-- Use this profile for any OpenShift specific customization your app will need. --> <!-- By default that is to put the resulting archive into the 'deployments' folder. --> <!-- http://maven.apache.org/guides/mini/guide-building-for-different-environments.html --> <id>openshift</id> <build> <plugins> <plugin> <artifactId>maven-ear-plugin</artifactId> <version>${version.ear.plugin}</version> <configuration> <outputDirectory>deployments</outputDirectory> </configuration> </plugin> </plugins> </build> </profile> </profiles> </project> 

pom.xml from ejb project:

 <?xml version="1.0" encoding="UTF-8"?> <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> <parent> <artifactId>demo-maven</artifactId> <groupId>com.comp.demo</groupId> <version>0.0.1-SNAPSHOT</version> </parent> <artifactId>demo-service</artifactId> <packaging>ejb</packaging> <name>demo - service</name> <url>www.comp.com</url> <licenses> <license> <name>Apache License, Version 2.0</name> <distribution>repo</distribution> <url>http://www.apache.org/licenses/LICENSE-2.0.html</url> </license> </licenses> <dependencies> <!-- Declare the APIs we depend on and need for compilation. All of them are provided by JBoss EAP 6 --> <!-- Import the EJB API, we use provided scope as the API is included in JBoss EAP 6 --> <dependency> <groupId>org.jboss.spec.javax.ejb</groupId> <artifactId>jboss-ejb-api_3.1_spec</artifactId> <scope>provided</scope> </dependency> <!-- Import the CDI API, we use provided scope as the API is included in JBoss EAP 6 --> <dependency> <groupId>javax.enterprise</groupId> <artifactId>cdi-api</artifactId> <scope>provided</scope> </dependency> <!-- Import the JPA API, we use provided scope as the API is included in JBoss EAP 6 --> <dependency> <groupId>org.hibernate.javax.persistence</groupId> <artifactId>hibernate-jpa-2.0-api</artifactId> <scope>provided</scope> </dependency> <!-- JSR-303 (Bean Validation) Implementation --> <!-- Provides portable constraints such as @Email --> <!-- Hibernate Validator is shipped in JBoss EAP 6 --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-validator</artifactId> <scope>provided</scope> </dependency> <dependency> <groupId>org.jboss.ejb3</groupId> <artifactId>jboss-ejb3-ext-api</artifactId> <version>2.0.0-redhat-2</version> <type>jar</type> <scope>provided</scope> </dependency> <!-- Test scope dependencies --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.mockito</groupId> <artifactId>mockito-all</artifactId> <version>1.9.5</version> <scope>test</scope> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>4.3.5.Final</version> <scope>test</scope> </dependency> <!-- Optional, but highly recommended --> <!-- Arquillian allows you to test enterprise code such as EJBs and Transactional(JTA) JPA from JUnit/TestNG --> <dependency> <groupId>org.jboss.arquillian.junit</groupId> <artifactId>arquillian-junit-container</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.jboss.arquillian.protocol</groupId> <artifactId>arquillian-protocol-servlet</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>javax</groupId> <artifactId>javaee-api</artifactId> <version>6.0</version> <type>jar</type> <scope>provided</scope> </dependency> </dependencies> <build> <finalName>${project.artifactId}</finalName> <plugins> <plugin> <artifactId>maven-ejb-plugin</artifactId> <version>${version.ejb.plugin}</version> <configuration> <!-- Tell Maven we are using EJB 3.1 --> <ejbVersion>3.1</ejbVersion> </configuration> </plugin> </plugins> </build> <profiles> <profile> <!-- The default profile skips all tests, though you can tune it to run just unit tests based on a custom pattern --> <!-- Seperate profiles are provided for running all tests, including Arquillian tests that execute in the specified container --> <id>default</id> <activation> <activeByDefault>true</activeByDefault> </activation> <build> <plugins> <plugin> <artifactId>maven-surefire-plugin</artifactId> <version>${version.surefire.plugin}</version> <configuration> <skip>true</skip> </configuration> </plugin> </plugins> </build> </profile> <profile> <!-- An optional Arquillian testing profile that executes tests in your JBoss EAP instance --> <!-- This profile will start a new JBoss EAP instance, and execute the test, shutting it down when done --> <!-- Run with: mvn clean test -Parq-jbossas-managed --> <id>arq-jbossas-managed</id> <dependencies> <dependency> <groupId>org.jboss.as</groupId> <artifactId>jboss-as-arquillian-container-managed</artifactId> <scope>test</scope> </dependency> </dependencies> </profile> <profile> <!-- An optional Arquillian testing profile that executes tests in a remote JBoss EAP instance --> <!-- Run with: mvn clean test -Parq-jbossas-remote --> <id>arq-jbossas-remote</id> <dependencies> <dependency> <groupId>org.jboss.as</groupId> <artifactId>jboss-as-arquillian-container-remote</artifactId> <scope>test</scope> </dependency> </dependencies> </profile> </profiles> </project> 

Answer 1

I have a project configuration very similar to yours: eclipse, Maven, JDK 1.6, JBoss EAP6.2, and I have the same problem with java.lang.NoClassDefFoundError when using enumeration in case of switch.

I found a workaround for this: generate an ear file (this is a war in my case) and install it manually from the JBoss administration console. I noticed that the war includes the necessary 1 dollar classes, and then you will not get an exception.

This is just a workaround, but it works for me. The good point about this solution is that subsequent deployments done through eclipse work!

I will listen to the answers to your question, because I want a real solution.

Answer 2

I had a similar problem, and a simple solution was to define Enum as public, not private.

(I did not have time to check, but I suspect that this will not cause the class to not be created as $ 1.class Name , but rather something like $ Enumname.class Name , which seemed to be the problem)