Windows->
Preferences->
Java->
Installed JREs->
...(default)->
Edit->
Program Files\Java\jre1.8.0_45\lib\rt.jar->
Source Attachment Configuration->
External location->
Program Files/Java/jdk1.8.0_20/src.zi
Windows->
Preferences->
Java->
Installed JREs->
...(default)->
Edit->
Program Files\Java\jre1.8.0_45\lib\rt.jar->
Source Attachment Configuration->
External location->
Program Files/Java/jdk1.8.0_20/src.zi