How to import com.sun.javadoc.* in eclipse?

Importing com.sun.javadoc eclipse report me this error "The import com.sun.javadoc cannot be roselved" it seems the package is not installed. Looking at the web sitehttp://download.oracle.com/javase/1.5.0/docs/guide/javadoc/doclet/spec/index.html?com/sun/javadoc/package-summary.html only the API are displayed but I cannot download anything. How can I do