Tomcat 6, Embedded JBoss, Hibernate (future Seam): slf4j LinkageError
Hello,
I'm new to Hibernate and especially setting up Tomcat 6 along with JBoss Embedded and Hibernate 3.5.4 (core) plus annotations and entitymanager (both 3.4.0). I put the JBoss embedded files into tomcat/lib as described here:
http://community.jboss.org/wiki/Tomcat60x
After that, I went to get my webapp to deploy, which I managed by using Ant deploy tasks and/or Tomcat's web interface (both work). Entering http://localhost:8080/bbstats gets me to the index.jsp, which is just static html in the following WAR structure:
root
+-- index.jsp
+-- META-INF
| +-- MANIFEST.MF
| +-- persistence.xml
+-- WEB-INF
+-- classes
| +-- com ...
+-- lib
| +-- antlr-2.7.6.jar
| +-- ... .jar
| +-- slf4j-api-1.5.8.jar
+-- web.xml
Note, that I'm manually managing the JARs just to get a feel for the material. I will look into Ivy or Maven at some point, but currently I want full control over what goes into my app. The JARs in WEB-INF/lib are:
antlr-2.7.6.jar
commons-collections-3.2.1.jar
commons-lang-2.5.jar
dom4j-1.6.1.jar
ejb3-persistence.jar
hibernate-annotations.jar
hibernate-commons-annotations.jar
hibernate-entitymanager.jar
hibernate3.jar
javassist-3.9.0.GA.jar
jsf-api.jar
jsf-facelets.jar
jsf-impl.jar
jta-1.1.jar
mysql-connector-java-5.1.13-bin.jar
slf4j-api-1.5.8.jar
When loading the servlet I get the following exception:
13.08.2010 13:21:38 org.apache.catalina.core.ApplicationContext log
INFO: Marking servlet Basketball Stats as unavailable
13.08.2010 13:21:38 org.apache.catalina.core.StandardContext loadOnStartup
SCHWERWIEGEND: Servlet /bbstats threw load() exception
java.lang.LinkageError: loader constraint violation: when resolving method "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader (instance of org/apache/catalina/loader/WebappClassLoader) of the current class, org/slf4j/LoggerFactory, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, org/slf4j/impl/StaticLoggerBinder, have different Class objects for the type org/slf4j/ILoggerFactory used in the signature
at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:274)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:242)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:255)
at org.hibernate.cfg.Configuration.<clinit>(Configuration.java:165)
at org.hibernate.ejb.Ejb3Configuration.<clinit>(Ejb3Configuration.java:107)
at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:124)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:52)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:34)
at com.mydomain.bbstats.servlet.BasketballStatsServlet.<init>(BasketballStatsServlet.java:33)
The code I use is:
public class BasketballStatsServlet extends HttpServlet
{
//@PersistenceContext
private EntityManagerFactory emf = Persistence.createEntityManagerFactory("bbstats");
public BasketballStatsServlet()
{
...
The persistence context seems to be initialized correctly. (Note, that using @PersistenceContext doesn't seem to be supported by Tomcat).
Now what this means is that there seem to be two slf4j JARs on the classpath. So I thought, well, let me just remove that JAR from my webapp classpath and it should be ok. However, if I omit the slf4j-api-1.5.8.jar for example, Tomcat throws an exception saying
13.08.2010 14:18:12 org.apache.catalina.core.ApplicationContext log
INFO: Marking servlet Basketball Stats as unavailable
13.08.2010 14:18:12 org.apache.catalina.core.StandardContext loadOnStartup
SCHWERWIEGEND: Servlet /bbstats threw load() exception
javax.persistence.PersistenceException: No Persistence provider for EntityManager named bbstats
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:56)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:34)
at com.mydomain.bbstats.servlet.BasketballStatsServlet.<init>(BasketballStatsServlet.java:33)
This happens when Hibernate dependencies are missing. It concerns other JARs as well.
Now, I obviously have two of the same class trees on my classpath, but removing the one from my webapp produces even more serious results (the latter exception doesn't even reach the Hibernate code, compare the stack traces). I'm stuck. It appears as if the class loaders collide when slf4j-api.jar is present, but are unable to use the other slf4j jar when it's not in the webapp lib.
How can I resolve this?
I looked into the embedded JBoss JARs and thirdparty-all.jar includes slf4j, too. But I don't get why removing the slf4j JAR from the webapp lib dir doesn't work. Can anyone help, please?
Karsten
I'm new to Hibernate and especially setting up Tomcat 6 along with JBoss Embedded and Hibernate 3.5.4 (core) plus annotations and entitymanager (both 3.4.0). I put the JBoss embedded files into tomcat/lib as described here:
http://community.jboss.org/wiki/Tomcat60x
After that, I went to get my webapp to deploy, which I managed by using Ant deploy tasks and/or Tomcat's web interface (both work). Entering http://localhost:8080/bbstats gets me to the index.jsp, which is just static html in the following WAR structure:
root
+-- index.jsp
+-- META-INF
| +-- MANIFEST.MF
| +-- persistence.xml
+-- WEB-INF
+-- classes
| +-- com ...
+-- lib
| +-- antlr-2.7.6.jar
| +-- ... .jar
| +-- slf4j-api-1.5.8.jar
+-- web.xml
Note, that I'm manually managing the JARs just to get a feel for the material. I will look into Ivy or Maven at some point, but currently I want full control over what goes into my app. The JARs in WEB-INF/lib are:
antlr-2.7.6.jar
commons-collections-3.2.1.jar
commons-lang-2.5.jar
dom4j-1.6.1.jar
ejb3-persistence.jar
hibernate-annotations.jar
hibernate-commons-annotations.jar
hibernate-entitymanager.jar
hibernate3.jar
javassist-3.9.0.GA.jar
jsf-api.jar
jsf-facelets.jar
jsf-impl.jar
jta-1.1.jar
mysql-connector-java-5.1.13-bin.jar
slf4j-api-1.5.8.jar
When loading the servlet I get the following exception:
13.08.2010 13:21:38 org.apache.catalina.core.ApplicationContext log
INFO: Marking servlet Basketball Stats as unavailable
13.08.2010 13:21:38 org.apache.catalina.core.StandardContext loadOnStartup
SCHWERWIEGEND: Servlet /bbstats threw load() exception
java.lang.LinkageError: loader constraint violation: when resolving method "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader (instance of org/apache/catalina/loader/WebappClassLoader) of the current class, org/slf4j/LoggerFactory, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, org/slf4j/impl/StaticLoggerBinder, have different Class objects for the type org/slf4j/ILoggerFactory used in the signature
at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:274)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:242)
at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:255)
at org.hibernate.cfg.Configuration.<clinit>(Configuration.java:165)
at org.hibernate.ejb.Ejb3Configuration.<clinit>(Ejb3Configuration.java:107)
at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:124)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:52)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:34)
at com.mydomain.bbstats.servlet.BasketballStatsServlet.<init>(BasketballStatsServlet.java:33)
The code I use is:
public class BasketballStatsServlet extends HttpServlet
{
//@PersistenceContext
private EntityManagerFactory emf = Persistence.createEntityManagerFactory("bbstats");
public BasketballStatsServlet()
{
...
The persistence context seems to be initialized correctly. (Note, that using @PersistenceContext doesn't seem to be supported by Tomcat).
Now what this means is that there seem to be two slf4j JARs on the classpath. So I thought, well, let me just remove that JAR from my webapp classpath and it should be ok. However, if I omit the slf4j-api-1.5.8.jar for example, Tomcat throws an exception saying
13.08.2010 14:18:12 org.apache.catalina.core.ApplicationContext log
INFO: Marking servlet Basketball Stats as unavailable
13.08.2010 14:18:12 org.apache.catalina.core.StandardContext loadOnStartup
SCHWERWIEGEND: Servlet /bbstats threw load() exception
javax.persistence.PersistenceException: No Persistence provider for EntityManager named bbstats
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:56)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:34)
at com.mydomain.bbstats.servlet.BasketballStatsServlet.<init>(BasketballStatsServlet.java:33)
This happens when Hibernate dependencies are missing. It concerns other JARs as well.
Now, I obviously have two of the same class trees on my classpath, but removing the one from my webapp produces even more serious results (the latter exception doesn't even reach the Hibernate code, compare the stack traces). I'm stuck. It appears as if the class loaders collide when slf4j-api.jar is present, but are unable to use the other slf4j jar when it's not in the webapp lib.
How can I resolve this?
I looked into the embedded JBoss JARs and thirdparty-all.jar includes slf4j, too. But I don't get why removing the slf4j JAR from the webapp lib dir doesn't work. Can anyone help, please?
Karsten