问题
I have a simple Spring MVC application that looks up some user details from an LDAP server and prints out a simple HTML page using a JSP. The application works fine on Tomcat 6. It uses Spring LDAP 1.3.1 and LDAPTemplate to do the LDAP lookups.
However, when I deploy this application WAR to Websphere 7, the app doesn't run -- Websphere returns a 500 Internal server error. Looking at Websphere's log file, I see
[14/12/10 14:50:09:169 GMT] 00000022 DispatcherSer E org.springframework.web.servlet.FrameworkServlet initServletBean Context initialization failed
org.springframework.beans.factory.CannotLoadBeanClassException: Error loading class [org.springframework.ldap.core.support.LdapContextSource] for bean with name 'contextSource' defined in ServletContext resource [/WEB-INF/spring-servlet.xml]: problem with class file or dependent class; nested exception is java.lang.NoClassDefFoundError: org.springframework.beans.factory.InitializingBean
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1253)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:576)
at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1319)
at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:885)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:562)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425)
My web-inf\lib directory has all the JAR files, including org.springframework.beans-3.0.5.RELEASE.jar, which contains InitializingBean. I'm therefore not sure why Websphere is reporting the class as missing.
Contents of my web-inf\lib:
aopalliance.jar
com.springsource.org.apache.commons.logging-1.1.1.jar
com.springsource.org.apache.log4j-1.2.15.jar
commons-lang-2.5.jar
commons-logging-1.1.1.jar
commons-pool-1.5.4.jar
jstl-api-1.2.jar
jstl-impl-1.2.jar
ldapbp-1.0.jar
org.springframework.aop-3.0.5.RELEASE.jar
org.springframework.asm-3.0.5.RELEASE.jar
org.springframework.beans-3.0.5.RELEASE.jar
org.springframework.context-3.0.5.RELEASE.jar
org.springframework.core-3.0.5.RELEASE.jar
org.springframework.expression-3.0.5.RELEASE.jar
org.springframework.jdbc-3.0.5.RELEASE.jar
org.springframework.oxm-3.0.5.RELEASE.jar
org.springframework.transaction-3.0.5.RELEASE.jar
org.springframework.web-3.0.5.RELEASE.jar
org.springframework.web.servlet-3.0.5.RELEASE.jar
spring-ldap-1.3.1.RELEASE-all.jar
And here's the definition of the contextSource bean which Websphere is having trouble loading (the username/password is valid and works with Tomcat):
<bean id="contextSource" class="org.springframework.ldap.core.support.LdapContextSource">
<property name="url" value="ldaps://moo.example.com:1300/" />
<property name="userDn" value="CN=foo,OU=baz,DC=bar,DC=blat,DC=org" />
<property name="password" value="*******" />
</bean>
I'd be very glad if someone could point out why this isn't working on Websphere. I'm not too sure about class-loading rules in Websphere and would appreciate any advice on this.
回答1:
Turn on Class Loading trace. This would tell you what classes are loaded and from which Jar. As Sajan mentioned chances are that there are duplicate jars in the classpath and the classloader that you expect has not loaded this class (and a parent class loader has likely loaded a class).
NoClassDefFoundError (NCDFE) does mean it could not locate the class that it is looking for. Errors in static initialization would explicitly turn out as a "java.lang.ExceptionInInitializerError" (EIIE) "
Both NCDFE and EIIE extend from Linkage error.
In general all these errors can easily be troubleshooted by turning on the class loading for the Server. Also use the Class Loader Viewer available in the admin console to aid in your troubleshooting activities.
HTH Manglu
回答2:
This is a sticky and common exception. Remember, that NoClassDefFoundError doesn't mean the class was not found, rather it means:
NoClassDefFoundError: The given class could be found, but something went wrong when initializing it (an interface it implemented could not be found, something went wrong in a static initializer etc.).
From here.
回答3:
Please check that you don't have the same class in any other possible jar
回答4:
Please check if you have added the dependencies in pom.xml file.
来源：https://stackoverflow.com/questions/4446050/noclassdeffounderror-in-websphere-jars-are-present