Log4j2 java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/type/TypeReference

问题

When I run my app on eclipse IDE, everything goes ok, but when I package it I get that exception. Then, if I package it again with jackson's dependencies in my pom I don't have any problem, but I would like to know why when I run it on my IDE even without jackson's dependencies no exception is thrown. The dependency tree is:

[INFO] +- org.hibernate:hibernate-entitymanager:jar:5.0.2.Final:compile
[INFO] |  +- org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile
[INFO] |  +- org.hibernate:hibernate-core:jar:5.0.2.Final:compile
[INFO] |  |  +- antlr:antlr:jar:2.7.7:compile
[INFO] |  |  \- org.jboss:jandex:jar:1.2.2.Final:compile
[INFO] |  +- dom4j:dom4j:jar:1.6.1:compile
[INFO] |  |  \- xml-apis:xml-apis:jar:1.0.b2:compile
[INFO] |  +- org.hibernate.common:hibernate-commons-annotations:jar:5.0.0.Final:compile
[INFO] |  +- org.hibernate.javax.persistence:hibernate-jpa-2.1-api:jar:1.0.0.Final:compile
[INFO] |  +- org.apache.geronimo.specs:geronimo-jta_1.1_spec:jar:1.1.1:compile
[INFO] |  \- org.javassist:javassist:jar:3.18.1-GA:compile
[INFO] +- org.apache.logging.log4j:log4j-api:jar:2.4.1:compile
[INFO] +- org.apache.logging.log4j:log4j-core:jar:2.4.1:compile
[INFO] +- org.slf4j:slf4j-simple:jar:1.7.13:compile
[INFO] |  \- org.slf4j:slf4j-api:jar:1.7.13:compile
[INFO] +- javax.mail:mail:jar:1.4.1:compile
[INFO] |  \- javax.activation:activation:jar:1.1:compile
[INFO] \- postgresql:postgresql:jar:9.1-901.jdbc4:compile

Stacktrace:

ERROR StatusLogger No log4j2 configuration file found. Using default configuration: logging only errors to the console.
Exception in thread "main" javax.persistence.PersistenceException: Unable to build entity manager factory
        at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:66)
        at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
        at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:39)
        at br.com.testejpa.view.Main.main(Main.java:15)
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [org.apache.logging.log4j.core.appender.db.jpa.converter.ContextMapJsonAttributeConverter]
        at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:232)
        at org.hibernate.boot.model.process.internal.ScanningCoordinator.applyScanResultsToManagedResources(ScanningCoordinator.java:235)
        at org.hibernate.boot.model.process.internal.ScanningCoordinator.coordinateScan(ScanningCoordinator.java:81)
        at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.prepare(MetadataBuildingProcess.java:98)
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.<init>(EntityManagerFactoryBuilderImpl.java:194)
        at org.hibernate.jpa.boot.spi.Bootstrap.getEntityManagerFactoryBuilder(Bootstrap.java:34)
        at org.hibernate.jpa.HibernatePersistenceProvider.getEntityManagerFactoryBuilder(HibernatePersistenceProvider.java:165)
        at org.hibernate.jpa.HibernatePersistenceProvider.getEntityManagerFactoryBuilderOrNull(HibernatePersistenceProvider.java:114)
        at org.hibernate.jpa.HibernatePersistenceProvider.getEntityManagerFactoryBuilderOrNull(HibernatePersistenceProvider.java:71)
        at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:52)
        ... 3 more
Caused by: java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/type/TypeReference
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:226)
        ... 12 more
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.core.type.TypeReference
        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)
        ... 15 more

回答1:

Do you use JSON layout or JSON configuration?

Dependencies per log4j feature are documented here: http://logging.apache.org/log4j/2.x/runtime-dependencies.html

回答2:

Try this:

Below

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.2.10.Final</version>
    </dependency>

add:

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.0</version>
        <scope>runtime</scope>
    </dependency>

来源：https://stackoverflow.com/questions/34374214/log4j2-java-lang-noclassdeffounderror-com-fasterxml-jackson-core-type-typerefer