Hibernate 3.4 with slf4j and log4j

Question

I'm attempting to upgrade from Hibernate 3.2 to 3.4, which apparently uses slf4j. Our project currently uses log4j. So my assumption is that I should be using the slf4j-log4j12 wrapped implementation.

The Maven slf4j dependency is:

<dependency>
    <groupId>org.slf4j</groupId>
     <artifactId>slf4j-log4j12</artifactId>
    <version>1.5.6</version>
</dependency>

While the log4j dependency is:

<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.15</version>
</dependency>

Both slf4j-log4j12 and log4j reference the latest version (that I could find in the Maven repository). When I run my app, Hibernate fails in its logging:

java.lang.NoSuchFieldError: name
    at org.slf4j.impl.Log4jLoggerAdapter.<init>(Log4jLoggerAdapter.java:75)
    at org.slf4j.impl.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:75)
    at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:103)
    at org.hibernate.cfg.Configuration.<clinit>(Configuration.java:163)
    ...

What am I missing?

Edit 1: If I remove the log4j dependency from my pom.xml I get the error:

java.lang.IllegalAccessError: tried to access field org.slf4j.impl.StaticLoggerBinder.SINGLETON from class org.slf4j.LoggerFactory
    at org.slf4j.LoggerFactory.<clinit>(LoggerFactory.java:60)
    at org.hibernate.cfg.Configuration.<clinit>(Configuration.java:163)
    ...

Edit 2: This blog claims the problem is caused by hibernate annotations shipping with the wrong version of slf4j-api.jar.

Answer 1

i have no problems with

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>3.3.1.GA</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-annotations</artifactId>
        <version>3.4.0.GA</version>
    </dependency>

and

     <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.5.6</version>
    </dependency>
    <!-- concrete Log4J Implementation for SLF4J API-->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.5.6</version>
    </dependency>

Answer 2

This question is answered by the SLF4J FAQ. Please see

http://slf4j.org/faq.html#compatibility and http://slf4j.org/faq.html#IllegalAccessError

Answer 3

I think you need to exclude the built-in SLF4J dependency from each of the Hibernate dependencies.

I use Hibernate with JPA, so my config isn't identical, but I think the crucial thing is to explicitly include log4j and SLF4J and explicitly exclude slf4j-api from all org.hibernate dependencies:

    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.15</version>
        <scope>compile</scope>
        <exclusions>
            <exclusion>
                <groupId>com.sun.jmx</groupId>
                <artifactId>jmxri</artifactId>
            </exclusion>
            <exclusion>
                <groupId>javax.jms</groupId>
                <artifactId>jms</artifactId>
            </exclusion>
            <exclusion>
                <groupId>com.sun.jdmk</groupId>
                <artifactId>jmxtools</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-annotations</artifactId>
        <version>3.4.0.GA</version>
        <exclusions>
            <exclusion>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-api</artifactId>
            </exclusion>
        </exclusions>
        <scope>compile</scope>
    </dependency>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>3.4.0.GA</version>
        <exclusions>
            <exclusion>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-api</artifactId>
            </exclusion>
        </exclusions>
        <scope>compile</scope>
    </dependency>

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.5.6</version>
        <scope>runtime</scope>
    </dependency>

Answer 4

After checking the version 1.5.6 POM for slf4j-log4j (and then slf4j-parent) you should be using log4j-1.2.14. The slf4j-log4j POM uses dependency management to inherit the appropriate version of log4j from the slf4j-parent POM.

You shouldn't, however, need to include log4j as a specific dependency as it is already a dependency of slf4j-log4j. That may have been where you caused your problem.