The difference between Java application Library and Java Web Lib

I remebered that I had writed a Java Web programming. At this time, I added jar packages by "build path" so that I could import a the user library path at firstly.

When the path of the jar library had been imported in Eclipse,to Complise program is right, but it is wrong to run at the Tomcat server.

So I would like to know what leads the condition. Then I found the answer in the web,finally, I summary following contents by different answers some people on the web.

I have known this eclipse project only copys the path of the jar Library,so it shall not add these jars into the project. Then I can programming rightly in the editor.

But I must run Web project on the server, which has own class loader. and the server to load jars at the Lib, which is under Web-inf. Therefore, we have to add extend jar packages into the Lib folder when we editor Web programming.

Finally, it leads to a condition so we can compile programming in Eclipse,but can not run on the server cause of Finding not jar packages.

NOTICE:I has to obye the rulers that special framework, beacuse different frameworks has different running mechanism.

The difference between Java application Library and Java Web Lib