salut
j ai un message d'erreur quand j essaie de lance mon application

public List<Person> SearchUsPerson(String filter) throws org.apache.lucene.queryParser.ParseException{
EntityManager em = null ;
MultiFieldQueryParser parser;
org.apache.lucene.search.Query query = null;
FullTextEntityManager fullTextEntityManager;
javax.persistence.Query persistenceQuery;

//Définition des champs de recherche
String[] fields = new String[]{"name","fisrtname"};
parser = new MultiFieldQueryParser(fields, new StandardAnalyzer());
try {
query = parser.parse(filter);
} catch (ParseException ex) {
throw new RuntimeException("Cannot search with query string",ex);
}
//création du fullTextEntityManager
fullTextEntityManager = Search.getFullTextEntityManager(em);
persistenceQuery = fullTextEntityManager.createFullTextQuery(query,Person.class).setCriteriaQuery(null);
//récupération des résultats
return persistenceQuery.getResultList();
}
java.lang.NullPointerException
java.io.StringReader.<init>(StringReader.java:33)
org.apache.lucene.queryParser.QueryParser.parse(QueryParser.java:167)
com.utile.ElementSearch.SearchUsPerson(ElementSearch.java:49)
org.apache.jsp.Recherche_jsp._jspService(Recherche_jsp.java:92)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)