HTTP Status 500 - Servlet execution threw an exception In tomcat7

Question

I'm trying to retrieve all elements in database and display in webpage.But now it was producing the error HTTP Status 500 - Servlet execution threw an exception. Can anyone tell me how to fix this error. Please help me.

Stack Trace :

javax.servlet.ServletException: Servlet execution threw an exception
   root cause

java.lang.NoClassDefFoundError: com/google/gson/JsonObject
skypark.RetriveIm.doGet(RetriveIm.java:64)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
  root cause

java.lang.ClassNotFoundException: com.google.gson.JsonObject
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
skypark.RetriveIm.doGet(RetriveIm.java:64)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

The complete source code is in this question

This is the #64 line Gson gson=new Gson(); Please help me........Thanks....

The exception stack trace itself indicates what the hell is going on under the hood - `java.lang.NoClassDefFoundError: com/google/gson/JsonObject`. — Lion, Feb 09 '13 at 11:28
How do you install/deploy the servlet code in the tomcat server? — Clemens Klein-Robbenhaar, Feb 09 '13 at 14:50

score 1 · Answer 1 · answered Feb 09 '13 at 11:22

1

Add library for Gson to you classpath. Either to your webapp (WEB-INF/lib) or to the classpath of your AS.

answered Feb 09 '13 at 11:22

Jiri Kremser

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I have added gson 2.2 jar file in my project library. Please tell me then why this showing the error. – James Feb 09 '13 at 12:13
Check the content of the jar if the class `com/google/gson/JsonObject` is there. If not download some other version, where it is for instance 2.1 (http://www.jarvana.com/jarvana/view/com/google/code/gson/gson/2.1/gson-2.1-sources.jar!/com/google/gson/JsonObject.java?format=ok). – Jiri Kremser Feb 09 '13 at 20:01
btw. what do you mean by "adding the jar to the project library"? You have to add it to the `WEB-INF/lib` directory in the war file or the the common lib path for Tomcat. – Jiri Kremser Feb 09 '13 at 20:04

score 1 · Accepted Answer · answered Feb 09 '13 at 11:23

1

You're compiling against the jar providing com.google.gson.JsonObject (or a dependent) but not deploying it at runtime. It needs to be deployed such that that class can be found/loaded by the classloader when run against.

answered Feb 09 '13 at 11:23

Brian Agnew

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I have added gson 2.2 jar file in my project library. Please tell me then why this showing the error. – James Feb 09 '13 at 12:12

Sudhakar · Answer 3 · 2013-02-10T14:41:16.467

1

Assuming your using Eclipse and the project configured as Dynamic Web Project Right click on your project --> choose configure build path --> now click on add jars button --> and select the Gson jar --> clickOK.

Republish the project and restart the server.

Else add the jar to WEB-INF\lib directoryinside the war

Or directly into the Deployed location in the tomcat , but in the same directory as mentioned

edited Feb 10 '13 at 14:41

answered Feb 10 '13 at 14:18

Sudhakar

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HTTP Status 500 - Servlet execution threw an exception In tomcat7

3 Answers3