Here is two ways of doing it:
1. Turn the JAR-file(s) into plugin(s)
This is probably the simplest solution, but maybe not always achieving the desired granularity though. "Use New" -> "Project" -> "Plug-in Development" -> "Plug-in from existing JAR Archive". That will turn the JAR-file into a single JAR-plugin. Check that all required packages are re-exported.
2. Include the JAR-file(s) in the plugin in question:
- Use the "Import" -> "File System" to import the JAR-file(s) into your plugin project. E.g.
- Then use "Add..." to add the JAR-file(s) to the classpath section of the Manifest/plugin.xml runtime tab.
- Press "New..." to add "." library back to the the classpath (without quotes).
- Check that the binary build exports the new JAR-file(s) on the Build tab.
- Press save, important for the changes to come through.
- Select the project in question in the package explorer view, right click and select "PDE Tools" -> "Update classpath". This will add the newly added JAR-file(s) to the project´s classpath.