FULL PRODUCT VERSION :
java version "1.8.0_91"
Java(TM) SE Runtime Environment (build 1.8.0_91-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.91-b14, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.3.9600]

A DESCRIPTION OF THE PROBLEM :
javadoc does not allow to link API docs where the path contains a space:

$ javadoc ... -link "file:///c:/Program%20Files/Java/jdk1.8.0_91/docs/api"
generates dead links to
c:/Program%25%20Files/Java/jdk1.8.0_91/docs/api

It does not help to use a space or + character instead of %20.
This bug was introduced with Java 1.8. Java 1.7.0_51 produces correct javadoc HTML. (Java 1.7 also allowed to use the space character.)

ADDITIONAL REGRESSION INFORMATION:
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
javadoc -d javadoc\api -sourcepath src -subpackages mypackage -link "file:///c:/Program%20Files/Java/jdk1.8.0_91/docs/api"


REPRODUCIBILITY :
This bug can be reproduced always.