Question

I tried to migrate to Solr 3.1 , my project uses Dataimport handler ,
when I started solr it asked me SolrCoreAwar not found I copied the following file to lib directory
apache-solr-dataimporthandler-3.1-SNAPSHOT.jar
but again an error appeared when stating solr
I need to fix this problem , if you can help
Thank You

The next message is the exception I get When Starting Solr 3.1

 java.lang.NoClassDefFoundError: Could not initialize class org.slf4j.LoggerFactory
    at org.apache.solr.handler.dataimport.DataImportHandler.<clinit>(DataImportHandler.java:72)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at org.apache.solr.core.SolrResourceLoader.findClass(SolrResourceLoader.java:373)
    at org.apache.solr.core.SolrCore.createInstance(SolrCore.java:423)
    at org.apache.solr.core.SolrCore.createRequestHandler(SolrCore.java:459)
    at org.apache.solr.core.RequestHandlers.initHandlersFromConfig(RequestHandlers.java:154)
    at org.apache.solr.core.SolrCore.<init>(SolrCore.java:563)
    at org.apache.solr.core.CoreContainer.create(CoreContainer.java:458)
    at org.apache.solr.core.CoreContainer.load(CoreContainer.java:316)
    at org.apache.solr.core.CoreContainer.load(CoreContainer.java:207)
    at org.apache.solr.core.CoreContainer$Initializer.initialize(CoreContainer.java:130)
    at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:94)
    at org.mortbay.jetty.servlet.FilterHolder.doStart(FilterHolder.java:97)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:713)
    at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
    at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1282)
    at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:518)
    at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:499)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:152)
    at org.mortbay.jetty.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:156)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:152)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
    at org.mortbay.jetty.Server.doStart(Server.java:224)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.xml.XmlConfiguration.main(XmlConfiguration.java:985)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at org.mortbay.start.Main.invokeMain(Main.java:194)
    at org.mortbay.start.Main.start(Main.java:534)
    at org.mortbay.start.Main.start(Main.java:441)
    at org.mortbay.start.Main.main(Main.java:119

Update

I’ve added the following jar files to my class path , the previous exception disappeared , but a new Error appeared when starting solr server :

 Error Instantiating Request Handler, org.apache.solr.handler.dataimport.DataImportHandler is not a org.apache.solr.request.SolrRequestHandler
    at org.apache.solr.core.SolrCore.createInstance(SolrCore.java:425)
    at org.apache.solr.core.SolrCore.createRequestHandler(SolrCore.java:459)
    at org.apache.solr.core.RequestHandlers.initHandlersFromConfig(RequestHandlers.java:154)
    at org.apache.solr.core.SolrCore.<init>(SolrCore.java:563)
    at org.apache.solr.core.CoreContainer.create(CoreContainer.java:458)
    at org.apache.solr.core.CoreContainer.load(CoreContainer.java:316)
    at org.apache.solr.core.CoreContainer.load(CoreContainer.java:207)
    at org.apache.solr.core.CoreContainer$Initializer.initialize(CoreContainer.java:130)
    at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:94)
    at org.mortbay.jetty.servlet.FilterHolder.doStart(FilterHolder.java:97)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:713)
    at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
    at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1282)
    at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:518)
    at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:499)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:152)
    at org.mortbay.jetty.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:156)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:152)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
    at org.mortbay.jetty.Server.doStart(Server.java:224)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
        at org.mortbay.xml.XmlConfiguration.main(XmlConfiguration.java:985)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at org.mortbay.start.Main.invokeMain(Main.java:194)
    at org.mortbay.start.Main.start(Main.java:534)
    at org.mortbay.start.Main.start(Main.java:441)
    at org.mortbay.start.Main.main(Main.java:119)

Answer 1

The problem is now solved.

This problem occurred because dataimporthandler and requesthandler are loaded by two different class loaders. To solve it, ensure that solr loads its jars only from the same class loader.

First of all I ensured that :

1) In solrconfig.xml remove ensure that dataimporthandler only comes from one place
2) I have commented all directives and added new one that refers to lib directory in solr directory so the lib directory path is example/solr/lib , this directory doesn’t exists by default. Create it (for example using mkdir solr/lib) and the lib directive in solrconfig.xml becomes

<lib dir="./solr/lib"/>   

3) Add the jar file from dist directory to this directory example/solr/lib
4) Fire up your solr server

And don’t forget to copy your mysql-driver jar to your include path to be able to index your mysql database tables if you use dataimporthandler for this purpose

Note: This works for solr 4.0