eclipse3.7纯净版升级了windowbuild，没有javadoc。解决办法

eclipse3.7纯净版升级了windowbuild，没有javadoc。
eclipse3.7纯净版升级了windowbuild，没有javadoc。

例如：button

org.eclipse.swt.widgets.Button
Note: This element has no attached Javadoc and the Javadoc could not be found in the attached source

这个javadoc应该要怎么弄？

------解决方案--------------------
下载src包吧，啥都有了