How to attach source or JavaDoc in eclipse for any jar file e.g. JavaFX?

1. Download jar file containing the JavaDocs.
2. Open the Build Path page of the project (right click, properties, Java build path).
3. Open the Libraries tab.
4. Expand the node of the library in question (JavaFX).
5. Select JavaDoc location and click edit.
6. Enter the location to the file which contains the Javadoc (the one you just downloaded).

You can configure the Javadocs with downloading jar, basically javadocs will be referred directly from internet.

Complete steps:

1. Open the Build Path page of the project (right click, properties,Java build path).
2. Open the Libraries tab.
3. Expand the node of the library in question (JavaFX).
4. Select JavaDoc location and click edit.
5. Enter the location to the file which contains the Javadoc.Specifically for the javaFX javadoc enter http://docs.oracle.com/javafx/2.0/api/

for offline javadocs, you can download from : http://www.oracle.com/technetwork/java/javase/documentation/java-se-7-doc-download-435117.html

After clicking Accept License Agreement you can download javafx-2_2_0-apidocs.zip

Neither Project/Properties/Javadoc Location nor Project/Properties/Java Build Path/Libraries had not helped me until I picked and moved up in "Order and Export" tab of "Java Build Path" "Android Dependencies" and added-in-library.jar. I hope it will be useful.