Why I can't get the doc that added recently by IndexWriter in the search result in Lucene 4.0?

Why I can't get the doc that added recently by IndexWriter in the search
result in Lucene 4.0?

References

Reference NO 1

http://stackoverflow.com/questions/15197028/why-i-cant-get-the-doc-that-added-recently-by-indexwriter-in-the-search-result

Reference NO 2

http://stackoverflow.com/questions/6403606/lucene-java-opening-too-many-files-am-i-using-indexwriter-properly

Reference NO 3

http://stackoverflow.com/questions/16847857/how-do-you-read-the-index-in-lucene-to-do-a-search

Reference NO 4

http://stackoverflow.com/questions/16582055/lucene-prevent-some-fields-to-highlight

Reference NO 5

http://stackoverflow.com/questions/10439505/how-to-delete-a-document-using-indexwriter-in-lucenenet

Reference NO 6

#EANF#

Reference NO 7

#EANF#

Reference NO 8

#EANF#