Java Firebase错误“ NoClassDefFoundError：org / apache / http / conn / ssl / StrictHostnameVerifier”

Question

I have a very simple servlet program running normally on google app engine. Now when i add firebase object to make a child value updation call it shows server error 500 on appengine and on local apache tomcat it also shows some error. Here is my code

package com.example.appengine.helloworld;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.firebase.client.Firebase;
import com.firebase.client.FirebaseException;

@SuppressWarnings("serial")
public class HelloServlet extends HttpServlet {

  @Override
  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException,FirebaseException  {


    PrintWriter out = resp.getWriter();
    out.println("Hello, world");
    Firebase fire = new Firebase("https://fiery-fire-0.firebaseio.com/");
    fire.child("hello").setValue("Nothing is in here");   
  }
}

here is the error when running it on apache tomcat

    Exception in thread "TubeSockReader-1" java.lang.NoClassDefFoundError: org/apache/http/conn/ssl/StrictHostnameVerifier
    at com.firebase.tubesock.WebSocket.verifyHost(WebSocket.java:287)
    at com.firebase.tubesock.WebSocket.createSocket(WebSocket.java:271)
    at com.firebase.tubesock.WebSocket.runReader(WebSocket.java:306)
    at com.firebase.tubesock.WebSocket.access$000(WebSocket.java:30)
    at com.firebase.tubesock.WebSocket$2.run(WebSocket.java:108)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: org.apache.http.conn.ssl.StrictHostnameVerifier
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1854)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1703)
    ... 6 more

On running it on google app engine it simply says

Error: Server Error

The server encountered an error and could not complete your request.
Please try again in 30 seconds.

Kindly help me!

Answer 1

It looks like the version of your http client library doesn't have the (now deprecated) class StrictHostnameVerifier.

https://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/org/apache/http/conn/ssl/StrictHostnameVerifier.html

Try manually including httpclient 4.0.1 instead of "latest" (although it should appear in 4.5.1 according the docs).