title: No class definition found error occurs while trying to run the lucene app from command line
body: <p>I'm a beginner to lucene and I had tried to run a sample app (HelloLucene.java) given in the website <a href="http://www.lucenetutorial.com/lucene-in-5-minutes.html" rel="nofollow noreferrer">http://www.lucenetutorial.com/lucene-in-5-minutes.html</a>. The code was successfully compiled and a class file (HelloLucene.class)  was created for the app. </p>
  
  <p>But while trying to run the app, following error occurs </p>
  
  <ul>
  <li>could not find or load main class HelloLucene</li>
  </ul>
  
  <p>I had referred with the link <a href="https://stackoverflow.com/questions/9258005/java-program-uses-or-overrides-a-deprecated-api">Java program uses or overrides a deprecated API?</a> and tried the solutions provided, but all in vain. please help me to solve this problem.</p>
  
  <p>The command which I used to run the code is</p>
  
  <ul>
  <li>java HelloLucene lucene</li>
  </ul>
  
  <p>code which I tried to run:</p>
  
  <pre><code>import org.apache.lucene.analysis.standard.StandardAnalyzer;
  import org.apache.lucene.document.Document;
  import org.apache.lucene.document.Field;
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.index.IndexWriter;
  import org.apache.lucene.index.IndexWriterConfig;
  import org.apache.lucene.queryParser.ParseException;
  import org.apache.lucene.queryParser.QueryParser;
  import org.apache.lucene.search.IndexSearcher;
  import org.apache.lucene.search.Query;
  import org.apache.lucene.search.ScoreDoc;
  import org.apache.lucene.search.TopScoreDocCollector;
  import org.apache.lucene.store.Directory;
  import org.apache.lucene.store.RAMDirectory;
  import org.apache.lucene.util.Version;
  
  import java.io.IOException;
  
  public class HelloLucene {
    public static void main(String[] args) throws IOException, ParseException {
  // 0. Specify the analyzer for tokenizing text.
  //    The same analyzer should be used for indexing and searching
  StandardAnalyzer analyzer = new StandardAnalyzer(Version.LUCENE_35);
  
  // 1. create the index
  Directory index = new RAMDirectory();
  
  IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_35, analyzer);
  
  IndexWriter w = new IndexWriter(index, config);
  addDoc(w, "Lucene in Action");
  addDoc(w, "Lucene for Dummies");
  addDoc(w, "Managing Gigabytes");
  addDoc(w, "The Art of Computer Science");
  w.close();
  
  // 2. query
  String querystr = args.length &gt; 0 ? args[0] : "lucene";
  
  // the "title" arg specifies the default field to use
  // when no field is explicitly specified in the query.
  Query q = new QueryParser(Version.LUCENE_35, "title", analyzer).parse(querystr);
  
  // 3. search
  int hitsPerPage = 10;
  IndexReader reader = IndexReader.open(index);
  IndexSearcher searcher = new IndexSearcher(reader);
  TopScoreDocCollector collector = TopScoreDocCollector.create(hitsPerPage, true);
  searcher.search(q, collector);
  ScoreDoc[] hits = collector.topDocs().scoreDocs;
  
  // 4. display results
  System.out.println("Found " + hits.length + " hits.");
  for(int i=0;i&lt;hits.length;++i) {
    int docId = hits[i].doc;
    Document d = searcher.doc(docId);
    System.out.println((i + 1) + ". " + d.get("title"));
  }
  
  // searcher can only be closed when there
  // is no need to access the documents any more. 
  searcher.close();
  }
  
   private static void addDoc(IndexWriter w, String value) throws IOException {
     Document doc = new Document();
     doc.add(new Field("title", value, Field.Store.YES, Field.Index.ANALYZED));
     w.addDocument(doc);
   }
  }
  </code></pre>