I am trying to apply patch LUCENE-2899.patch to Solr.
I have done this:
As you can see on LUCENE-2899, the patch is already applied to 8.0 (master), as well as 7.3.
You can find pre-built nightlies at Solr-Artifacts-master for (currently) 8.0 and at Solr-Artifacts-7.3 for 7.3.
The opennlp libraries are bundled inside the artifacts:
solr-8.0.0-3304 find . -name '*nlp*'
[...]
./contrib/langid/lib/opennlp-tools-1.8.3.jar
./contrib/analysis-extras/lib/opennlp-maxent-3.0.3.jar
./contrib/analysis-extras/lib/opennlp-tools-1.8.3.jar
./contrib/analysis-extras/lucene-libs/lucene-analyzers-opennlp-8.0.0-3304.jar
You then have to tell Solr to load these jars, which you can do through solrconfig.xml.
<lib dir="../../../contrib/analysis-extras/lib/" regex="opennlp-.*\.jar" />
<lib dir="../../../contrib/analysis-extras/lucene-libs/lucene-analyzers-opennlp-.*\.jar" regex=".*\.jar" />
Confirm that the jars are loaded as you expect in Solr's log file.