HTTP状态500 - Servlet执行引发异常在tomcat7中

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....

Answer 1

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

Answer 2

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.

Answer 3

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 --> click OK .

Republish the project and restart the server.

Else add the jar to WEB-INF\\lib directory inside the war

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