Apache Tomcat 8 not working. Throws HTTP Status 500 - java.lang.ClassNotFoundException: org.apache.jsp.index_jsp

Question 1

IT'S WORKING!

What I did:

Opened command prompt using "Run as administrator"

Went to the "bin" directory of Tomcat folder.

cd C:\Program Files\apache-tomcat-8.0.3\bin'

Entered 'startup' to run 'startup.bat' and the server started
Opened a web browser entered http://localhost:8080/ and it worked like charm. This also started generating Tomcat log files too.

The only different thing I performed is "Run as administrator".

But I checked with Tomcat7 it did not require me to "Run as administrator" but it worked; not sure why

Question 2

Check the lib folder of your tomcat installation. It must contain the JARs jasper-el.jar, jasper.jar, and jsp-api.jar. If they exist, maybe you should add Tomcat 8 in the Java Build Path for your project.

EDIT:

What you can do is to run shutdown.bat. Then look for a file called catalina.out in the logs folder of your tomcat installation. Open it in a text editor, delete all of its contents and save. Then try running startup.bat again. Next copy the contents of catalina.out and paste them here. This may help other people solve your problem.

Question 3

I had the very same error attempting to reach the manager URL (actually, 404 then 500 after page refresh, each single time). I thought it was <SERVER_BASE_URL>/manager/. It turns out it was <SERVER_BASE_URL>/manager/html.

It’s worth mentioning it wouldn’t tell me I wasn’t using the right credentials either.

Question 4

Simple, A ClassNotFoundException throws when some where a class that is used in the code is missing.

EG : If it is for servlet, then it means something servlet api that is regularly available to tomcat is now missing for some reason.

quite possibly the servlet-api.jar file in tomcat's lib folder (maybe other jar files in the tomcat lib folder) have become corrupted or removed.

Find it, you'll fix that.