Adding Documents to Solr by using Java Client API is failed

[Andy Tang]

I have the code to add document to Solr. I tested it in Both Solr 6.6.2 and
Solr 7.2.1 and failed.

import java.io.IOException;  import
org.apache.solr.client.solrj.SolrClient; import
org.apache.solr.client.solrj.SolrServerException; import
org.apache.solr.client.solrj.impl.HttpSolrClient; import
org.apache.solr.common.SolrInputDocument;
public class AddingDocument {
   public static void main(String args[]) throws Exception {

String urlString ="http://localhost:8983/solr/Solr_example";;
     SolrClient Solr = new HttpSolrClient.Builder(urlString).build();

      //Preparing the Solr document
      SolrInputDocument doc = new SolrInputDocument();

      //Adding fields to the document
      doc.addField("id", "007");
      doc.addField("name", "James Bond");
      doc.addField("age","45");
      doc.addField("addr","England");

      //Adding the document to Solr
      Solr.add(doc);

      //Saving the changes
      Solr.commit();
      System.out.println("Documents added");
   } }

The compilation is successful like below.

javac -cp .:/opt/solr/solr-6.6.2/dist/solr-solrj-6.6.2.jar
AddingDocument.java

However, when I run it, it gave me some errors message confused.

java -cp .:/opt/solr/solr-6.6.2/dist/solr-solrj-6.6.2.jar AddingDocument

Exception in thread "main" java.lang.NoClassDefFoundError:
org/apache/http/Header
    at 
org.apache.solr.client.solrj.impl.HttpSolrClient$Builder.build(HttpSolrClient.java:892)
    at AddingDocument.main(AddingDocument.java:13)Caused by:
java.lang.ClassNotFoundException: org.apache.http.Header
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 2 more

What is wrong with it? Is this urlString correct?

Any help is appreciated!
Andy Tang