Lucene indexWriter update does not affect Solr search - solr

Question

I implement a small code for the purpose of extracting some keywords out of Lucene index. I did implement that using search component. My problem is when I tried to update Lucene IndexWriter, Solr index which is placed on top of that, does not affect. As you can see I did the commit part.
BooleanQuery query = new BooleanQuery();
for (String fieldName : keywordSourceFields) {
TermQuery termQuery = new TermQuery(new Term(fieldName,"N/A"));
query.add(termQuery, Occur.MUST_NOT);
}
TermQuery termQuery=new TermQuery(new Term(keywordField, "N/A"));
query.add(termQuery, Occur.MUST);
try {
//Query q= new QueryParser(keywordField, new StandardAnalyzer()).parse(query.toString());
TopDocs results = searcher.search(query,
maxNumDocs);
ScoreDoc[] hits = results.scoreDocs;
IndexWriter writer = getLuceneIndexWriter(searcher.getPath());
for (int i = 0; i < hits.length; i++) {
Document document = searcher.doc(hits[i].doc);
List<String> keywords = keyword.getKeywords(hits[i].doc);
if(keywords.size()>0) document.removeFields(keywordField);
for (String word : keywords) {
document.add(new StringField(keywordField, word, Field.Store.YES));
}
String uniqueKey = searcher.getSchema().getUniqueKeyField().getName();
writer.updateDocument(new Term(uniqueKey, document.get(uniqueKey)),
document);
}
writer.commit();
writer.forceMerge(1);
writer.close();
} catch (IOException | SyntaxError e) {
throw new RuntimeException();
}
private IndexWriter getLuceneIndexWriter(String indexPath) throws IOException {
FSDirectory directory = FSDirectory.open(new File(indexPath).toPath());
Analyzer analyzer = new StandardAnalyzer();
IndexWriterConfig iwc = new IndexWriterConfig(analyzer);
return new IndexWriter(directory, iwc);
}
Please help me through solving this problem.
Update:
I did some investigation and found out that the retrieving part of documents works fine while Solr did not restarted. But the searching part of documents did not work. After I restarted Solr it seems that the core corrupted and failed to start! Here is the corresponding log:
org.apache.solr.common.SolrException: Error opening new searcher
at org.apache.solr.core.SolrCore.<init>(SolrCore.java:896)
at org.apache.solr.core.SolrCore.<init>(SolrCore.java:662)
at org.apache.solr.core.CoreContainer.create(CoreContainer.java:513)
at org.apache.solr.core.CoreContainer$1.call(CoreContainer.java:278)
at org.apache.solr.core.CoreContainer$1.call(CoreContainer.java:272)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Caused by: org.apache.solr.common.SolrException: Error opening new searcher
at org.apache.solr.core.SolrCore.openNewSearcher(SolrCore.java:1604)
at org.apache.solr.core.SolrCore.getSearcher(SolrCore.java:1716)
at org.apache.solr.core.SolrCore.<init>(SolrCore.java:868)
... 9 more
Caused by: org.apache.lucene.index.IndexNotFoundException: no segments* file found in NRTCachingDirectory(MMapDirectory#C:\Users\Ali\workspace\lucene_solr_5_0_0\solr\server\solr\document\data\index lockFactory=org.apache.lucene.store.SimpleFSLockFactory#3bf76891; maxCacheMB=48.0 maxMergeSizeMB=4.0): files: [_2_Lucene50_0.doc, write.lock, _2_Lucene50_0.pos, _2.nvd, _2.fdt, _2_Lucene50_0.tim]
at org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:821)
at org.apache.solr.update.SolrIndexWriter.<init>(SolrIndexWriter.java:78)
at org.apache.solr.update.SolrIndexWriter.create(SolrIndexWriter.java:65)
at org.apache.solr.update.DefaultSolrCoreState.createMainIndexWriter(DefaultSolrCoreState.java:272)
at org.apache.solr.update.DefaultSolrCoreState.getIndexWriter(DefaultSolrCoreState.java:115)
at org.apache.solr.core.SolrCore.openNewSearcher(SolrCore.java:1573)
... 11 more
4/7/2015, 6:53:26 PM
ERROR
SolrIndexWriter
SolrIndexWriter was not closed prior to finalize(),​ indicates a bug -- POSSIBLE RESOURCE LEAK!!!
4/7/2015, 6:53:26 PM
ERROR
SolrIndexWriter
Error closing IndexWriter
java.lang.NullPointerException
at org.apache.lucene.index.IndexWriter.doFlush(IndexWriter.java:2959)
at org.apache.lucene.index.IndexWriter.flush(IndexWriter.java:2927)
at org.apache.lucene.index.IndexWriter.shutdown(IndexWriter.java:965)
at org.apache.lucene.index.IndexWriter.close(IndexWriter.java:1010)
at org.apache.solr.update.SolrIndexWriter.close(SolrIndexWriter.java:130)
at org.apache.solr.update.SolrIndexWriter.finalize(SolrIndexWriter.java:183)
at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:101)
at java.lang.ref.Finalizer.access$100(Finalizer.java:32)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:190)
There for my guess would be problem with indexing the keywordField and also problem related to closing the IndexWriter.