It sounds like you are attempting to add the jzos library into your OSGi bundle in the lib folder. Normally what we would expect to do is a wrapper OSGi bundle that is used within the IDE. This wrapper bundle exports the com.ibm.jzos classes and your bundle imports them. This should allow the compiling and IDE to be happy.

For full instructions have a look at https://www.ibm.com/docs/en/cics-ts/6.x?topic=djariojs-developing-java-applications-use-jzos-toolkit-api-in-osgi-jvm-server