With Hadoop, Lucene, Solr, etc. written in Java, there is no doubt that Java is here to stay. None of these libraries (or many others) have competing implementations written in other languages.
Except the ones they were written to copy. Each example you give is an open-sourced clone of an pre-existing version implemented in a different language.
Though I agree with OP - these projects and Java are here to stay for the foreseeable future.