FAQ How do I add an extra library to my project's classpath?
Open the context menu on the project, and select Properties > Java Build Path > Libraries. From here, you can add JAR files to the build path, whether they are inside your workspace or not. You can also add a class folder, a directory containing Java class files that are not in a JAR. Note that plug-in development has more restrictions on where build path entries can come from. For plug-in projects, you should always let the plug-in development tools organize your build path for you. Simply select the plugin.xml file, and choose PDE Tools > Update Classpath from the context menu.