The package org.w3c.dom is accessible from more than one module: <unnamed>, java.xml ~ Find and exclude dependency

Question

I know there's already some topics on issues like these, but the case I've come across is somehow different.

It starts with this error message:

import org.w3c.dom.Element;
The package org.w3c.dom is accessible from more than one module: <unnamed>, java.xml

I know that the following dependency "causes" this, because if I remove it, this error disapperas (and many others pop up):

compile "org.eclipse.lyo.clients:oslc-java-client:2.4.0"

I have already tried this:

    compile ("org.eclipse.lyo.clients:oslc-java-client:2.4.0") {
        exclude group: "org.w3c.dom", module: "org.w3c.dom"
    }

However, that did not change anything about the issue.

I have tried listing the transitive dependencies using gradle dependencies , which returned me this dependency tree for the OSLC Java Client:

+--- org.eclipse.lyo.clients:oslc-java-client:2.4.0
|    +--- org.slf4j:slf4j-api:1.7.25
|    +--- org.apache.jena:apache-jena-libs:3.6.0
|    |    +--- org.apache.jena:jena-tdb:3.6.0
|    |    |    +--- org.apache.jena:jena-arq:3.6.0
|    |    |    |    +--- org.apache.jena:jena-core:3.6.0
|    |    |    |    |    +--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    |    +--- org.apache.jena:jena-iri:3.6.0
|    |    |    |    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    |    +--- xerces:xercesImpl:2.11.0
|    |    |    |    |    |    \--- xml-apis:xml-apis:1.4.01
|    |    |    |    |    +--- commons-cli:commons-cli:1.4
|    |    |    |    |    \--- org.apache.jena:jena-base:3.6.0
|    |    |    |    |         +--- org.apache.jena:jena-shaded-guava:3.6.0
|    |    |    |    |         |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    |         +--- org.apache.commons:commons-csv:1.5
|    |    |    |    |         +--- commons-io:commons-io:2.6
|    |    |    |    |         +--- org.apache.commons:commons-lang3:3.4
|    |    |    |    |         +--- com.github.andrewoma.dexx:collection:0.7
|    |    |    |    |         \--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    +--- org.apache.jena:jena-shaded-guava:3.6.0 (*)
|    |    |    |    +--- org.apache.httpcomponents:httpclient:4.5.3
|    |    |    |    |    +--- org.apache.httpcomponents:httpcore:4.4.6
|    |    |    |    |    +--- commons-logging:commons-logging:1.2
|    |    |    |    |    \--- commons-codec:commons-codec:1.9
|    |    |    |    +--- com.github.jsonld-java:jsonld-java:0.11.1
|    |    |    |    |    +--- com.fasterxml.jackson.core:jackson-core:2.9.0
|    |    |    |    |    +--- com.fasterxml.jackson.core:jackson-databind:2.9.0
|    |    |    |    |    |    +--- com.fasterxml.jackson.core:jackson-annotations:2.9.0
|    |    |    |    |    |    \--- com.fasterxml.jackson.core:jackson-core:2.9.0
|    |    |    |    |    +--- org.slf4j:jcl-over-slf4j:1.7.25
|    |    |    |    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    |    \--- commons-io:commons-io:2.5 -> 2.6
|    |    |    |    +--- org.apache.httpcomponents:httpclient-cache:4.5.3
|    |    |    |    |    \--- org.apache.httpcomponents:httpclient:4.5.3 (*)
|    |    |    |    +--- org.apache.thrift:libthrift:0.10.0
|    |    |    |    |    +--- org.slf4j:slf4j-api:1.7.12 -> 1.7.25
|    |    |    |    |    \--- org.apache.httpcomponents:httpclient:4.4.1 -> 4.5.3 (*)
|    |    |    |    +--- org.slf4j:jcl-over-slf4j:1.7.25 (*)
|    |    |    |    +--- org.apache.commons:commons-lang3:3.4
|    |    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    +--- org.apache.jena:jena-tdb2:3.6.0
|    |    |    +--- org.apache.jena:jena-dboe-trans-data:3.6.0
|    |    |    |    +--- org.apache.jena:jena-dboe-transaction:3.6.0
|    |    |    |    |    +--- org.apache.jena:jena-dboe-base:3.6.0
|    |    |    |    |    |    +--- org.apache.jena:jena-arq:3.6.0 (*)
|    |    |    |    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    +--- org.apache.jena:jena-dboe-index:3.6.0
|    |    |    |    |    +--- org.apache.jena:jena-dboe-base:3.6.0 (*)
|    |    |    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    +--- org.apache.jena:jena-rdfconnection:3.6.0
|    |    |    +--- org.apache.jena:jena-arq:3.6.0 (*)
|    |    |    \--- org.slf4j:slf4j-api:1.7.25
|    |    \--- org.slf4j:slf4j-api:1.7.25
|    +--- net.oauth.core:oauth:20100527
|    +--- net.oauth.core:oauth-consumer:20100527
|    |    \--- net.oauth.core:oauth:20100527
|    +--- net.oauth.core:oauth-httpclient4:20090913
|    |    +--- net.oauth.core:oauth-consumer:20090617 -> 20100527 (*)
|    |    \--- org.apache.httpcomponents:httpclient:4.0 -> 4.5.3 (*)
|    +--- org.apache.wink:wink-client:1.4 (*)
|    +--- org.apache.wink:wink-client-apache-httpclient:1.4
|    |    +--- org.apache.wink:wink-client:1.4 (*)
|    |    \--- org.apache.httpcomponents:httpclient:4.1.3 -> 4.5.3 (*)
|    +--- org.eclipse.lyo.oslc4j.core:oslc4j-core:2.4.0
|    |    +--- javax.ws.rs:jsr311-api:1.1.1
|    |    +--- org.apache.jena:apache-jena-libs:3.6.0 (*)
|    |    +--- org.slf4j:slf4j-api:1.7.25
|    |    \--- org.assertj:assertj-core:3.8.0
|    +--- org.eclipse.lyo.oslc4j.core:oslc4j-jena-provider:2.4.0
|    |    +--- org.eclipse.lyo.oslc4j.core:oslc4j-core:2.4.0 (*)
|    |    +--- xml-apis:xml-apis:1.3.04 -> 1.4.01
|    |    +--- xerces:xercesImpl:2.8.0 -> 2.11.0 (*)
|    |    +--- org.slf4j:slf4j-api:1.7.25
|    |    \--- org.apache.jena:apache-jena-libs:3.6.0 (*)
|    +--- org.eclipse.lyo.oslc4j.core:oslc4j-json4j-provider:2.4.0
|    |    +--- org.eclipse.lyo.oslc4j.core:oslc4j-core:2.4.0 (*)
|    |    \--- org.apache.wink:wink-json4j:1.2.1-incubating
|    +--- org.apache.httpcomponents:httpcore:4.4.5 -> 4.4.6
|    +--- org.apache.httpcomponents:httpclient:4.5.2 -> 4.5.3 (*)
|    +--- xerces:xercesImpl:2.8.0 -> 2.11.0 (*)
|    +--- xml-apis:xml-apis:1.3.04 -> 1.4.01
|    +--- javax.servlet:javax.servlet-api:3.1.0
|    \--- javax.ws.rs:jsr311-api:1.1.1

Now, what baffles me is that w3c does not seem to exist anywhere in that tree. How is that possible? I know for a fact that removing this dependencies resolves the w3c conflict, so logically it has to be in there somewhere, or am I missing something?

Does anyone have any idea how this can be and what can be done about it?

Answer 1

I now managed to figure out how to fix it, even though I don't have a perfect understanding how the fix relates to the problem.

The bottom line is that the transitive dependency on xml-apis somehow caused this, even though xml-apis does not seem to have any dependencies on its own. So writing the dependency like this fixed the issue for me:

    compile ("org.eclipse.lyo.clients:oslc-java-client:2.4.0"){
        exclude module: "xml-apis"
    }

Does anyone have a more satisfying explanation for this? Thus far, all I know is that xml-apis ( https://mvnrepository.com/artifact/xml-apis/xml-apis/1.4.01 ) does not seem to have any dependencies, however , it does for some reason use the W3C License.