Uses of different “lib” folders in WSO2 Carbon

WSO2 Carbon is the OSGi based platform for all WSO2 java products. In Carbon, there are four different “lib” folders. If you have ever tried any of the Carbon based products, you may have thought “why are there four different libs?”. If so, this post will provide you the answer for that question.

These are the “lib” folders that you can find in Carbon.

[1] CARBON_HOME/webapps/ROOT/WEB-INF/lib

Carbon is a web app which is deployed in an embedded tomcat instance. This is the lib folder which is specific to Carbon web app just like any other web app has in WEB-INF/lib folder. Bridge servlet is the one who forwards each and every incoming request into the OSGi environment of Carbon. We have used this lib to place our Bridge Servlet. Tomcat pics it up from there and hands over the incoming requests to it.

[2] CARBON_HOME/repository/components/lib

This is the place to put your normal jars if you want them to become pure bundles in the OSGi environment. All packages in these bundles are exported into the OSGi environment. As you may know, Carbon can be extended as you wish. You can add your own bundles into it. So If you have dependent jars for those bundles, you can place those in this lib.

[3] CARBON_HOME/repository/lib

This is the place where all client libraries exist. When you run ‘ant’ from CARBON_HOME/bin, all needed jars are put into this folder. If you want to write a client (or you can generate it using the WSDL2Java tool in WSAS) and test it, the set of all jars you need in the classpath can be found in this lib. For example, WSAS samples are run by adding all these libs into client classpath.


This is the place where we put all jars which are needed by tomcat to start and some others for specific reasons. This is same as the Tomcat root lib. These libraries can be seen from all webapps deployed. And also, if you place the same jar in this lib and also inside Carbon web app, it will be picked up from this root lib as Tomcat uses parent first class loading.


About isurues
Age : 24 Date of Birth : 05.11.1984 Country : Sri Lanka

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