Hi Thorsten,
I think this might be related to the modularization of SolrJ that occurred in
Solr 10, though I'm not entirely certain.
- Jetty-based HTTP clients were apparently moved to a separate package:
org.apache.solr.solrj.jetty
- These clients now seem to require a separate Maven artifact: solr-solrj-jetty
- ZooKeeper dependencies were possibly split into: solr-solrj-zookeeper
- The core solr-solrj might now have minimal dependencies and only includes
HttpJdkSolrClient
It looks like the Maven POM for SolrJ in Solr 10 deliberately no longer
includes transitive dependencies for Jetty HttpClient, ZooKeeper, etc. I found
a reference in the changelog:
"Starting in 10, the Maven POM for SolrJ does not refer to SolrJ modules like
ZooKeeper. If you require such functionality, you need to add additional
dependencies."
Maybe add:
<dependency>
<groupId>org.apache.solr</groupId>
<artifactId>solr-solrj-jetty</artifactId>
<version>${solr.version}</version>
</dependency>
And possibly if you're using CloudSolrClient with ZooKeeper:
<dependency>
<groupId>org.apache.solr</groupId>
<artifactId>solr-solrj-zookeeper</artifactId>
<version>${solr.version}</version>
</dependency>
This could explain why you had to add all those dependencies manually as they
used to be automatically included via the old monolithic SolrJ dependency
structure.
Worth checking if this resolves your issue...
On Mon, Mar 9, 2026, at 1:05 PM, Thorsten Heit wrote:
> Hi Chip,
>
> > Your analysis is correct - you're experiencing these dependency issues
> > because Solr 10 has made significant changes to the Tika integration
> > architecture.
> >
> > In Solr 9.10, the LocalTikaExtractionBackend was deprecated, and in Solr
> > 10.0.0 it has been completely removed (SOLR-17961). This is indeed what's
> > causing your ClassNotFoundException and the need to manually add all those
> > dependencies.
> >
> > Key changes in Solr 10:
> > • LocalTikaExtractionBackend (in-process Tika) is removed
> > • Only the external TikaServer backend is now supported
> > • The ExtractingRequestHandler now requires configuring an external Tika
> > Server URL via the 'tikaserver.url' parameter
> > • Parse-context-based configuration is no longer supported
>
> (...)
>
> > 2. **Alternative extraction pipeline**: Extract content in your application
> > before sending to Solr, which is often more robust for production anyway.
> >
> > The dependency explosion you're seeing is because the local Tika backend
> > used to handle these dependencies transparently, but now they're exposed
> > due to the architectural changes.
>
> Yes I know. When I saw that there's a new release I first read the
> changelog. But IMHO this isn't the problem I'm seeing:
>
> Before I upload documents to Solr, I use a local Tika parser to extract
> content (I don't use Solr for this), I'm sending preprocessed
> SolrDocuments containing all the information.
>
> OTOH when you compare the pom.xml files for solr-core for versions
> 9.10.1 and 10.0.0 they don't look much different. As far as I have seen
> they both contain more or less the same dependencies with the same
> scope, some of them have newer versions. What I don't understand is that
> all those dependencies aren't available in the dependency tree in my test.
>
>
> With solr-core-9.10.1 "mvn dependency:tree" gives me
>
> (...)
> [INFO] +- org.apache.solr:solr-core:jar:9.10.1:compile
> [INFO] | +- org.apache.lucene:lucene-core:jar:9.12.2:compile
> [INFO] | +- org.apache.lucene:lucene-analysis-common:jar:9.12.2:compile
> [INFO] | +- org.apache.lucene:lucene-queries:jar:9.12.3:compile
> (...)
> [INFO] | \- org.xerial.snappy:snappy-java:jar:1.1.10.8:runtime
> [INFO] +- org.eclipse.jdt:org.eclipse.jdt.annotation:jar:2.4.100:provided
> [INFO] +- org.junit.jupiter:junit-jupiter-engine:jar:6.0.3:test
> [INFO] | +- org.junit.platform:junit-platform-engine:jar:6.0.3:test
> [INFO] | | +- org.opentest4j:opentest4j:jar:1.3.0:test
> [INFO] | | \- org.junit.platform:junit-platform-commons:jar:6.0.3:test
> [INFO] | +- org.junit.jupiter:junit-jupiter-api:jar:6.0.3:test
> [INFO] | +- org.apiguardian:apiguardian-api:jar:1.1.2:test
> [INFO] | \- org.jspecify:jspecify:jar:1.0.0:runtime
> [INFO] \- org.junit.jupiter:junit-jupiter-params:jar:6.0.3:test
> (...)
>
> whereas the same command with solr-core-10.0.0 only shows
>
> (...)
> [INFO] +- org.apache.solr:solr-core:jar:10.0.0:compile
> [INFO] +- org.eclipse.jdt:org.eclipse.jdt.annotation:jar:2.4.100:provided
> [INFO] +- org.junit.jupiter:junit-jupiter-engine:jar:6.0.3:test
> [INFO] | +- org.junit.platform:junit-platform-engine:jar:6.0.3:test
> [INFO] | | +- org.opentest4j:opentest4j:jar:1.3.0:test
> [INFO] | | \- org.junit.platform:junit-platform-commons:jar:6.0.3:test
> [INFO] | +- org.junit.jupiter:junit-jupiter-api:jar:6.0.3:test
> [INFO] | +- org.apiguardian:apiguardian-api:jar:1.1.2:test
> [INFO] | \- org.jspecify:jspecify:jar:1.0.0:runtime
> [INFO] \- org.junit.jupiter:junit-jupiter-params:jar:6.0.3:test
> (...)
>
> All dependencies from solr-core-10.0.0 are missing although they are
> still there in the pom.xml...
>
>
> Do you have any idea why?
>
>
> Regards
>
> Thorsten
>
>
> *Attachments:*
> • OpenPGP_0x5A54BBB878225E08.asc
> • OpenPGP_signature.asc
