Error ClassNotFoundException accessing jar in web project

Summary

Classes from 3rd party jar files are accessible when added to build path while running a standalone JUnit test, but "ClassNotFoundException" when accessed through plain old java objects from within a dynamic web project.

• IDE used: Eclipse
• Web Server: Apache 7

Details

My project required a lot of 3rd party jars, namely sqlite, eclipse jdt & jsoup开发者_JAVA技巧. I had created this project as a standalone project and all the classes from the jars were accessible fine.

But now I have copied the entire "src" folder into a "dynamic web project". I have created a folder "jars" which contains all these 3rd party jars and ensure that all of these are added to the build path by following these steps:

Project properties --> Java Build Path --> Libraries --> Add jars --> Select all the jar files from jars folder.

These jars are accessible fine when I run a standalone JUnit test inside the web project. Note that this junit test does not require a server by any means.

But when I try to "Run on Server.." , I keep on getting ClassNotFoundException like these for all the 3rd party classes:

java.lang.ClassNotFoundException: org.sqlite.JDBC
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1672)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1517)

I'm sure this has got to do something with my lack of knowledge of how applications are deployed on the web.

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The runtime classpath can be different from the build classpath. Create an explicit launch configuration. The default will start with the build classpath but you may have to manually tweak it to include those 3rd party jars.

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I've run into this problem before with Eclipse and the Web Server Tools project. Check your .settings files and other files for configuring the plugins that you're using with your project. You may have to remove some filters in the Eclipse view. WST constructs its build path differently, so it may not be using the jars that you've included in your project.

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I figured it out. I just had to put all the jars in the WEB-INF/lib directory. I assumed that Eclipse would do all the required settings for me when I asked it to use the mentioned jars. But I guess there are somethings that are not automated very well.